diff --git a/app/Http/Controllers/Web/Auth/LoginCheckController.php b/app/Http/Controllers/Web/Auth/LoginCheckController.php
new file mode 100644
index 0000000..a2b1683
--- /dev/null
+++ b/app/Http/Controllers/Web/Auth/LoginCheckController.php
@@ -0,0 +1,66 @@
+<?php
+
+namespace App\Http\Controllers\Web\Auth;
+
+use App\Http\Controllers\Web\WebController;
+use App\Kintone\Models\Customer;
+use App\Models\User;
+use Illuminate\Http\JsonResponse;
+use Illuminate\Http\Request;
+use Illuminate\Support\Facades\Hash;
+
+class LoginCheckController extends WebController
+{
+
+    public function name(): string
+    {
+        return "ログインチェック";
+    }
+
+    public function description(): string
+    {
+        return "ログインチェックを行う";
+    }
+
+
+    public function __construct(protected LoginCheckParam $param)
+    {
+        parent::__construct();
+    }
+
+    protected function run(Request $request): JsonResponse
+    {
+        $param = $this->param;
+        // 取得したユーザ情報を登録しログインを行う
+
+
+        // ログインパスワードチェック
+        $users = User::whereEmail($param->email)
+            ->get();
+        foreach ($users as $user) {
+            info($user->toArray());
+            if (!Hash::check($param->password, $user->password)) {
+                return $this->failedResponse();
+            }
+        }
+
+        $access = Customer::getAccess();
+        $query = Customer::getQuery()->where(Customer::FIELD_EMAIL, $param->email);
+
+        $customers = $access->all($query);
+
+        if ($customers->isEmpty()) {
+            return $this->failedResponse();
+        }
+
+        $ret = [];
+        foreach ($customers as $customer) {
+            $ret[] = [
+                'customer_code' => $customer->customerCode,
+                'name' => $customer->customerName,
+            ];
+        }
+
+        return $this->successResponse($ret);
+    }
+}
diff --git a/app/Http/Controllers/Web/Auth/LoginCheckParam.php b/app/Http/Controllers/Web/Auth/LoginCheckParam.php
new file mode 100644
index 0000000..b8e73dc
--- /dev/null
+++ b/app/Http/Controllers/Web/Auth/LoginCheckParam.php
@@ -0,0 +1,20 @@
+<?php
+
+namespace App\Http\Controllers\Web\Auth;
+
+use App\Http\Controllers\Web\BaseParam;
+
+/**
+ * @property string $email
+ * @property string $password
+ */
+class LoginCheckParam extends BaseParam
+{
+    public function rules(): array
+    {
+        return [
+            'email' => $this->str(),
+            'password' => $this->str(),
+        ];
+    }
+}
diff --git a/app/Http/Controllers/Web/Auth/LoginController.php b/app/Http/Controllers/Web/Auth/LoginController.php
index 1b2b9e0..75f314e 100644
--- a/app/Http/Controllers/Web/Auth/LoginController.php
+++ b/app/Http/Controllers/Web/Auth/LoginController.php
@@ -2,15 +2,13 @@
 
 namespace App\Http\Controllers\Web\Auth;
 
-use App\Codes\EnvironmentName;
 use App\Http\Controllers\Web\WebController;
 use App\Kintone\Models\Customer;
 use App\Models\User;
-use Exception;
 use Illuminate\Http\JsonResponse;
 use Illuminate\Http\Request;
 use Illuminate\Support\Facades\Auth;
-use League\CommonMark\Environment\Environment;
+use Illuminate\Support\Facades\Hash;
 
 class LoginController extends WebController
 {
@@ -37,7 +35,8 @@ class LoginController extends WebController
         $param = $this->param;
 
         $access = Customer::getAccess();
-        $query = Customer::getQuery()->where(Customer::FIELD_EMAIL, $param->email);
+        $query = Customer::getQuery()->where(Customer::FIELD_EMAIL, $param->email)
+            ->where(Customer::FIELD_CUSTOMER_CODE, $param->customerCode);
 
         $customer = $access->some($query);
 
@@ -53,46 +52,18 @@ class LoginController extends WebController
             ->first();
 
         if ($user instanceof User) {
-            // すでにユーザー登録されているケース
+            // パスワードチェック
+            if (!Hash::check($param->password, $user->password)) {
+                return $this->failedResponse();
+            }
 
-            //データ同期
+            //データ同期 Email
             if ($user->email !== $param->email) {
                 $user->email = $param->email;
                 $user->save();
             }
-            if ($user->kintone_customer_code !== $customer->getNumber(Customer::FIELD_CUSTOMER_CODE)) {
-                $user->kintone_customer_code = $customer->getNumber(Customer::FIELD_CUSTOMER_CODE);
-                $user->save();
-            }
-
-            if (Auth::attempt([
-                'email' => $param->email,
-                'password' => $param->password,
-            ])) {
-                return $this->successResponse($customer->toArray());
-            } else {
-                return $this->failedResponse();
-            }
-        } else if (app()->environment([EnvironmentName::LOCAL->value]) && $param->password === "testuser") {
-
-            // ローカル環境でのテストユーザー作成処理
-            $user = new User();
-            $user->email = $param->email;
-            $user->kintone_id = $customer->getRecordId();
-            $user->password = "testuser";
-            $user->kintone_customer_code = $customer->getNumber(Customer::FIELD_CUSTOMER_CODE);
-            $user->save();
-
-            if (Auth::attempt([
-                'email' => $param->email,
-                'password' => 'testuser',
-            ])) {
-                return $this->successResponse($customer->toArray());
-            } else {
-                return $this->failedResponse();
-            }
-        } else {
-            return $this->failedResponse();
+            Auth::login($user);
+            return $this->successResponse($customer->toArray());
         }
     }
 }
diff --git a/app/Http/Controllers/Web/Auth/LoginParam.php b/app/Http/Controllers/Web/Auth/LoginParam.php
index d7b071c..0e4d748 100644
--- a/app/Http/Controllers/Web/Auth/LoginParam.php
+++ b/app/Http/Controllers/Web/Auth/LoginParam.php
@@ -7,6 +7,7 @@ use App\Http\Controllers\Web\BaseParam;
 /**
  * @property string $email
  * @property string $password
+ * @property int $customerCode
  */
 class LoginParam extends BaseParam
 {
@@ -15,6 +16,7 @@ class LoginParam extends BaseParam
         return [
             'email' => $this->str(),
             'password' => $this->str(),
+            'customer_code' => $this->numeric(),
         ];
     }
 }
diff --git a/app/Http/Controllers/Web/Auth/PasswordSettingStartController.php b/app/Http/Controllers/Web/Auth/PasswordSettingStartController.php
index d0cb290..f31f9a5 100644
--- a/app/Http/Controllers/Web/Auth/PasswordSettingStartController.php
+++ b/app/Http/Controllers/Web/Auth/PasswordSettingStartController.php
@@ -8,6 +8,7 @@ use App\Logic\PasswordSettingManager;
 use App\Models\User;
 use Illuminate\Http\JsonResponse;
 use Illuminate\Http\Request;
+use Illuminate\Support\Collection;
 
 class PasswordSettingStartController extends WebController
 {
@@ -35,43 +36,48 @@ class PasswordSettingStartController extends WebController
         $access = Customer::getAccess();
         $query = Customer::getQuery()->where(Customer::FIELD_EMAIL, $param->email);
 
-        $customer = $access->some($query);
+        $customers = $access->all($query);
 
-        if ($customer->count() !== 1) {
+        if ($customers->isEmpty()) {
 
             // 無効なユーザだが、セキュリティ対策として成功と見せかける
             return $this->successResponse();
         }
 
-        $customer = $customer->first();
+        // トークン生成
+        $this->tokenGenerate($customers);
 
-        $kintoneId = $customer->getRecordId();
+        return $this->successResponse();
+    }
 
-        $user = User::whereKintoneId($kintoneId)
-            ->first();
+    /**
+     * Undocumented function
+     *
+     * @param Collection<int,Customer> $customers
+     * @return void
+     */
+    private function tokenGenerate(Collection $customers)
+    {
 
-        if ($user instanceof User) {
-            //データ同期
-            if ($user->email !== $param->email) {
-                $user->email = $param->email;
-                $user->save();
-            }
-            if ($user->kintone_customer_code !== $customer->getNumber(Customer::FIELD_CUSTOMER_CODE)) {
+        foreach ($customers as $customer) {
+            $kintoneId = $customer->getRecordId();
+
+            $user = User::whereKintoneId($kintoneId)
+                ->first();
+
+
+            if ($user instanceof User) {
+            } else {
+                // 新規の場合はユーザーを追加する
+                $user = new User();
+                $user->email = $customer->email;
+                $user->kintone_id = $customer->getRecordId();
                 $user->kintone_customer_code = $customer->getNumber(Customer::FIELD_CUSTOMER_CODE);
                 $user->save();
             }
-        } else {
-            // 新規の場合はユーザーを追加する
-            $user = new User();
-            $user->email = $param->email;
-            $user->kintone_id = $customer->getRecordId();
-            $user->kintone_customer_code = $customer->getNumber(Customer::FIELD_CUSTOMER_CODE);
-            $user->save();
-        }
 
-        // トークン生成
-        $this->manager->generate($user);
-
-        return $this->successResponse();
+            // トークン生成
+            $this->manager->generate($user);
+        }
     }
 }
diff --git a/app/Http/Controllers/Web/Auth/PasswordSettingVerifyController.php b/app/Http/Controllers/Web/Auth/PasswordSettingVerifyController.php
index d526a14..c20676c 100644
--- a/app/Http/Controllers/Web/Auth/PasswordSettingVerifyController.php
+++ b/app/Http/Controllers/Web/Auth/PasswordSettingVerifyController.php
@@ -3,9 +3,7 @@
 namespace App\Http\Controllers\Web\Auth;
 
 use App\Http\Controllers\Web\WebController;
-use App\Kintone\Models\Customer;
 use App\Logic\PasswordSettingManager;
-use App\Models\User;
 use Illuminate\Http\JsonResponse;
 use Illuminate\Http\Request;
 
@@ -22,7 +20,6 @@ class PasswordSettingVerifyController extends WebController
         return "パスワード設定手続きを認証する";
     }
 
-
     public function __construct(protected PasswordSettingVerifyParam $param, private PasswordSettingManager $manager)
     {
         parent::__construct();
@@ -32,13 +29,15 @@ class PasswordSettingVerifyController extends WebController
     {
         $param = $this->param;
 
-        $user = $this->manager->verify($param->token);
-        if ($user === null) {
+        $users = $this->manager->verify($param->token);
+        if ($users === null) {
             return $this->failedResponse();
         }
 
-        $user->password = $param->password;
-        $user->save();
+        foreach ($users as $user) {
+            $user->password = $param->password;
+            $user->save();
+        }
 
         return $this->successResponse();
     }
diff --git a/app/Http/Controllers/Web/Customer/ChangeEmailVerifyController.php b/app/Http/Controllers/Web/Customer/ChangeEmailVerifyController.php
index 26a55ba..c9853de 100644
--- a/app/Http/Controllers/Web/Customer/ChangeEmailVerifyController.php
+++ b/app/Http/Controllers/Web/Customer/ChangeEmailVerifyController.php
@@ -4,9 +4,9 @@ namespace App\Http\Controllers\Web\Customer;
 
 use App\Http\Controllers\Web\WebController;
 use App\Logic\EmailChangeManager;
+use App\Transmissions\HTICWeb\Sender;
 use Illuminate\Http\JsonResponse;
 use Illuminate\Http\Request;
-use Illuminate\Support\Facades\Auth;
 
 class ChangeEmailVerifyController extends WebController
 {
@@ -21,24 +21,20 @@ class ChangeEmailVerifyController extends WebController
         return "Emailの変更手続きを認証する";
     }
 
+    use Sender;
 
     public function __construct(protected ChangeEmailVerifyParams $param, private EmailChangeManager $manager)
     {
         parent::__construct();
-        // $this->middleware('auth:sanctum');
     }
 
     protected function run(Request $request): JsonResponse
     {
         $param = $this->param;
 
-        $ret = $this->manager
+        $customer = $this->manager
             ->verify($param->token);
 
-        if (!$ret) {
-            $this->failedResponse();
-        }
-
         return $this->successResponse();
     }
 }
diff --git a/app/Http/Controllers/Web/HTICWeb/UserRegisterParam.php b/app/Http/Controllers/Web/HTICWeb/UserRegisterParam.php
index 987de67..69bb54f 100644
--- a/app/Http/Controllers/Web/HTICWeb/UserRegisterParam.php
+++ b/app/Http/Controllers/Web/HTICWeb/UserRegisterParam.php
@@ -24,6 +24,7 @@ class UserRegisterParam extends BaseParam
             'address2' => $this->str(true),
             'address3' => $this->str(true),
             'phone_number' => $this->str(true),
+            'parent_user_id' => $this->str(true),
         ];
     }
 }
diff --git a/app/Kintone/Models/Customer.php b/app/Kintone/Models/Customer.php
index 66d607d..0476f7c 100644
--- a/app/Kintone/Models/Customer.php
+++ b/app/Kintone/Models/Customer.php
@@ -15,6 +15,7 @@ use Illuminate\Support\Facades\Auth;
  * @property string address
  * @property string bankBranchId
  * @property ?Carbon bankAccountRegisterRemaindDatetime
+ * @property ?int icSeasonTicektUserId
  */
 class Customer extends KintoneModel
 {
@@ -72,4 +73,9 @@ class Customer extends KintoneModel
             'customer_name_kana_hankaku' => mb_convert_kana($this->customerNameKana, "sk"),
         ];
     }
+
+    public function isHTICWebUser(): bool
+    {
+        return !!$this->icSeasonTicektUserId;
+    }
 }
diff --git a/app/Logic/EmailChangeManager.php b/app/Logic/EmailChangeManager.php
index edafa87..419c55d 100644
--- a/app/Logic/EmailChangeManager.php
+++ b/app/Logic/EmailChangeManager.php
@@ -82,7 +82,7 @@ class EmailChangeManager
 
         // トークン削除
         $model->delete();
-        return true;
+        return $customer;
     }
 
     /**
diff --git a/app/Logic/PasswordSettingManager.php b/app/Logic/PasswordSettingManager.php
index 6c929b4..73d38ee 100644
--- a/app/Logic/PasswordSettingManager.php
+++ b/app/Logic/PasswordSettingManager.php
@@ -6,6 +6,7 @@ use App\Email\Guests\PasswordSettingStart;
 use App\Models\PasswordSettingToken;
 use App\Models\User;
 use App\Util\DateUtil;
+use Illuminate\Support\Collection;
 use Illuminate\Support\Str;
 
 class PasswordSettingManager
@@ -31,20 +32,29 @@ class PasswordSettingManager
         $emailManager->confirm();
     }
 
-    public function verify(string $token): User|null
+    /**
+     * @param string $token
+     * @return Collection<int, User>|null
+     */
+    public function verify(string $token): Collection|null
     {
-        $model = PasswordSettingToken::whereToken($token)
+        $passwords =
+            PasswordSettingToken::whereToken($token)
             ->expiresIn()
-            ->first();
+            ->get();
 
-        if ($model === null) {
-            return null;
-        }
 
-        $user = User::whereId($model->user_id)->firstOrFail();
+        $users = User::whereIn(
+            User::COL_NAME_ID,
+            $passwords->pluck(PasswordSettingToken::COL_NAME_USER_ID)
+        )
+            ->get();
+
 
-        $model->delete();
+        foreach ($passwords as $password) {
+            $password->delete();
+        }
 
-        return $user;
+        return $users;
     }
 }
diff --git a/app/Models/User.php b/app/Models/User.php
index 77a62ed..b33495a 100644
--- a/app/Models/User.php
+++ b/app/Models/User.php
@@ -7,6 +7,7 @@ use App\Events\Model\CreatingEvent;
 use App\Events\Model\DeletedEvent;
 use App\Events\Model\UpdatingEvent;
 use App\Models\Feature\IModelFeature;
+use Eloquent;
 use Illuminate\Database\Eloquent\Concerns\HasUuids;
 use Illuminate\Database\Eloquent\Factories\HasFactory;
 use Illuminate\Database\Eloquent\SoftDeletes;
@@ -16,6 +17,9 @@ use Illuminate\Notifications\Notifiable;
 use Illuminate\Support\Facades\DB;
 use Laravel\Sanctum\HasApiTokens;
 
+/**
+ * @mixin Eloquent
+ */
 class User extends Authenticatable implements IModelFeature
 {
     use HasApiTokens, HasFactory, Notifiable, HasUuids, SoftDeletes;
diff --git a/database/migrations/2024_05_20_171900_dropunique_email.php b/database/migrations/2024_05_20_171900_dropunique_email.php
new file mode 100644
index 0000000..cbe08ed
--- /dev/null
+++ b/database/migrations/2024_05_20_171900_dropunique_email.php
@@ -0,0 +1,28 @@
+<?php
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\Schema;
+
+return new class extends Migration
+{
+    /**
+     * Run the migrations.
+     */
+    public function up(): void
+    {
+        Schema::table('users', function (Blueprint $table) {
+            $table->dropUnique("users_email_unique");
+        });
+    }
+
+    /**
+     * Reverse the migrations.
+     */
+    public function down(): void
+    {
+        Schema::table('users', function (Blueprint $table) {
+            $table->string('email')->unique()->change();
+        });
+    }
+};
diff --git a/routes/api.php b/routes/api.php
index def7c4e..d49a3bd 100644
--- a/routes/api.php
+++ b/routes/api.php
@@ -16,6 +16,7 @@ use Illuminate\Support\Facades\Route;
 
 
 RouteHelper::post('/login', App\Http\Controllers\Web\Auth\LoginController::class);
+RouteHelper::post('/login/check', App\Http\Controllers\Web\Auth\LoginCheckController::class);
 RouteHelper::get('/logout', App\Http\Controllers\Web\Auth\LogoutController::class);
 RouteHelper::get('/me', App\Http\Controllers\Web\Auth\MeController::class);