diff --git a/src/api/index.ts b/src/api/index.ts
index 1b0aa15..94e6fb8 100644
--- a/src/api/index.ts
+++ b/src/api/index.ts
@@ -27,6 +27,8 @@ export const ApiId = {
   RECEIPT_ISSUING_ORDER: id++,
   RECEIPT_ISSUING_ORDER_CREATE: id++,
   RECEIPT_ISSUING_ORDER_MAIL_POST_COMPLETE: id++,
+  RECEIPT_ISSUING_ORDER_HANDELRS: id++,
+  RECEIPT_ISSUING_ORDER_CHANGE_HANDELR: id++,
   DOWNLOAD_RECEIPT_LETTER: id++,
 
   CONTRACTS: id++,
diff --git a/src/api/receipt-issuing-order.ts b/src/api/receipt-issuing-order.ts
index 47e0003..b7194d1 100644
--- a/src/api/receipt-issuing-order.ts
+++ b/src/api/receipt-issuing-order.ts
@@ -1,5 +1,14 @@
-import { APICommonResponse, ApiId, HttpMethod, makeParam, request } from ".";
+import { Dictionary } from "@types";
+import {
+  APICommonResponse,
+  ApiId,
+  HttpMethod,
+  TimestampRequest,
+  makeParam,
+  request,
+} from ".";
 import { getUrl } from "./url";
+import { string } from "yup";
 
 export type ReceiptIssuingOrder = {
   id: string;
@@ -43,6 +52,11 @@ export type ReceiptIssuingOrder = {
   updated_at: string;
 };
 
+export type Handler = {
+  id: string;
+  name: string;
+};
+
 // 領収証発行一覧取得 -----------------------
 export type ReceiptIssuingOrdersRequest = {
   address?: string;
@@ -80,3 +94,35 @@ export const completeMailPost = async (data: MailPostCompleteRequest) => {
   });
   return res;
 };
+
+// 担当者一覧取得 -----------------------
+export type HandlersRequest = {};
+export type HandlersResponse = {
+  data: {
+    records: Handler[];
+  };
+} & APICommonResponse;
+
+export const getHandlers = async (data: HandlersRequest) => {
+  const res = await request<HandlersResponse>({
+    url: getUrl(ApiId.RECEIPT_ISSUING_ORDER_HANDELRS),
+    method: HttpMethod.GET,
+    data: makeParam(data),
+  });
+  return res;
+};
+
+// 担当者変更 -----------------------
+export type ChangeHandlerRequest = {
+  id: string;
+  handler_id: string;
+} & TimestampRequest;
+
+export const changeHandler = async (data: ChangeHandlerRequest) => {
+  const res = await request({
+    url: getUrl(ApiId.RECEIPT_ISSUING_ORDER_CHANGE_HANDELR),
+    method: HttpMethod.POST,
+    data: makeParam(data),
+  });
+  return res;
+};
diff --git a/src/api/url.ts b/src/api/url.ts
index e4dbe04..ad5d89d 100644
--- a/src/api/url.ts
+++ b/src/api/url.ts
@@ -15,6 +15,9 @@ const urls = {
   [A.RECEIPT_ISSUING_ORDER_MAIL_ORDER]: "receipt-issuing-order/mail-order",
   [A.RECEIPT_ISSUING_ORDER_MAIL_POST_COMPLETE]:
     "receipt-issuing-order/mail-complete",
+  [A.RECEIPT_ISSUING_ORDER_HANDELRS]: "receipt-issuing-order/handlers",
+  [A.RECEIPT_ISSUING_ORDER_CHANGE_HANDELR]:
+    "receipt-issuing-order/change-handler",
   [A.DOWNLOAD_RECEIPT_LETTER]: "receipt-letter/download",
 
   [A.RECEIPT_ISSUING_ORDERS]: "receipt-issuing-orders",
diff --git a/src/pages/dashboard/receipt-issuing-order/custom/hello-techno/detail.tsx b/src/pages/dashboard/receipt-issuing-order/custom/hello-techno/detail.tsx
index 7cb39f2..75cb215 100644
--- a/src/pages/dashboard/receipt-issuing-order/custom/hello-techno/detail.tsx
+++ b/src/pages/dashboard/receipt-issuing-order/custom/hello-techno/detail.tsx
@@ -27,6 +27,7 @@ import { formatDateStr, formatDateTimeStr } from "utils/datetime";
 import useMailPostCompleteDialog from "./hooks/useMailPostCompleteDialog";
 import { getFullUrl } from "api/url";
 import { ApiId } from "api";
+import useChangeHandlerDialog from "../../hooks/useChangeHandlerDialog";
 
 export default function ReceiptIssuingOrderDetail() {
   const { setHeaderTitle, setTabs } = useDashboard(
@@ -47,6 +48,10 @@ export default function ReceiptIssuingOrderDetail() {
     fetch();
   });
 
+  const changeHandlerDialog = useChangeHandlerDialog(order, () => {
+    fetch();
+  });
+
   const { callAPI, sending } = useAPICall({
     apiMethod: getReceiptIssuingOrders,
     onSuccess: (res) => {
@@ -79,7 +84,16 @@ export default function ReceiptIssuingOrderDetail() {
       {
         title: "担当者",
         value: order.handler_name,
-        // end: <Button sx={{ minWidth: 80 }}>担当変更</Button>,
+        end: (
+          <Button
+            sx={{ minWidth: 80 }}
+            onClick={() => {
+              changeHandlerDialog.open();
+            }}
+          >
+            担当変更
+          </Button>
+        ),
       },
       { title: "SMS送信先", value: order.sms_phone_number },
       { title: "依頼日", value: formatDateStr(order.order_datetime) },
@@ -182,94 +196,97 @@ export default function ReceiptIssuingOrderDetail() {
   }, [sending]);
 
   return (
-    <Box>
-      <Grid container spacing={2}>
-        <Grid item xs={12}>
-          <Stack direction="row" spacing={2}>
-            <Button onClick={() => navigate(-1)}>戻る</Button>
-          </Stack>
-        </Grid>
-        <Grid item xs={4}>
-          <Paper elevation={0} sx={{ border: "1px solid" }}>
-            <Stack spacing={2}>
-              <Typography
-                variant="h6"
-                fontWeight="bold"
-                sx={{ my: 2, textAlign: "center" }}
-              >
-                依頼内容
-              </Typography>
-              <SimpleDataList data={orderInfo} />
-              <Divider sx={{ my: 2 }} />
-              <Typography
-                variant="subtitle1"
-                sx={{ my: 2, textAlign: "center" }}
-              >
-                領収証情報
-              </Typography>
-              <SimpleDataList data={receiptInfo} />
+    <>
+      <Box>
+        <Grid container spacing={2}>
+          <Grid item xs={12}>
+            <Stack direction="row" spacing={2}>
+              <Button onClick={() => navigate(-1)}>戻る</Button>
             </Stack>
-          </Paper>
-        </Grid>
-        <Grid item xs={4}>
-          <Paper elevation={0} sx={{ pb: 2, border: "1px solid" }}>
-            <Stack spacing={2}>
-              <Typography
-                variant="h6"
-                fontWeight="bold"
-                sx={{ my: 2, textAlign: "center" }}
-              >
-                郵送管理
-              </Typography>
-              <SimpleDataList data={mailStatus1} />
-              {hasMailOrder && (
-                <>
-                  <Divider sx={{ my: 2 }} />
-                  <Typography
-                    variant="subtitle1"
-                    sx={{ my: 2, textAlign: "center" }}
-                  >
-                    郵送先
-                  </Typography>
-                  <SimpleDataList data={mailStatus2} />
-                  <Divider />
-                  <Stack direction="row" spacing={2} sx={{ px: 2 }}>
-                    <Button
-                      variant="contained"
-                      href={downloadUrl}
-                      target="_blank"
+          </Grid>
+          <Grid item xs={4}>
+            <Paper elevation={0} sx={{ border: "1px solid" }}>
+              <Stack spacing={2}>
+                <Typography
+                  variant="h6"
+                  fontWeight="bold"
+                  sx={{ my: 2, textAlign: "center" }}
+                >
+                  依頼内容
+                </Typography>
+                <SimpleDataList data={orderInfo} />
+                <Divider sx={{ my: 2 }} />
+                <Typography
+                  variant="subtitle1"
+                  sx={{ my: 2, textAlign: "center" }}
+                >
+                  領収証情報
+                </Typography>
+                <SimpleDataList data={receiptInfo} />
+              </Stack>
+            </Paper>
+          </Grid>
+          <Grid item xs={4}>
+            <Paper elevation={0} sx={{ pb: 2, border: "1px solid" }}>
+              <Stack spacing={2}>
+                <Typography
+                  variant="h6"
+                  fontWeight="bold"
+                  sx={{ my: 2, textAlign: "center" }}
+                >
+                  郵送管理
+                </Typography>
+                <SimpleDataList data={mailStatus1} />
+                {hasMailOrder && (
+                  <>
+                    <Divider sx={{ my: 2 }} />
+                    <Typography
+                      variant="subtitle1"
+                      sx={{ my: 2, textAlign: "center" }}
                     >
-                      印字
-                    </Button>
+                      郵送先
+                    </Typography>
+                    <SimpleDataList data={mailStatus2} />
+                    <Divider />
+                    <Stack direction="row" spacing={2} sx={{ px: 2 }}>
+                      <Button
+                        variant="contained"
+                        href={downloadUrl}
+                        target="_blank"
+                      >
+                        印字
+                      </Button>
 
-                    <Button
-                      variant="contained"
-                      onClick={postCompleteDialog.open}
-                    >
-                      投函完了
-                    </Button>
-                  </Stack>
-                  {postCompleteDialog.element}
-                </>
-              )}
-            </Stack>
-          </Paper>
-        </Grid>
-        <Grid item xs={4}>
-          <Paper elevation={0} sx={{ border: "1px solid" }}>
-            <Stack spacing={2}>
-              <Typography
-                variant="h6"
-                fontWeight="bold"
-                sx={{ my: 2, textAlign: "center" }}
-              >
-                各種アクション日時
-              </Typography>
-              <SimpleDataList data={actionDatetimes} />
-            </Stack>
-          </Paper>
+                      <Button
+                        variant="contained"
+                        onClick={postCompleteDialog.open}
+                      >
+                        投函完了
+                      </Button>
+                    </Stack>
+                    {postCompleteDialog.element}
+                  </>
+                )}
+              </Stack>
+            </Paper>
+          </Grid>
+          <Grid item xs={4}>
+            <Paper elevation={0} sx={{ border: "1px solid" }}>
+              <Stack spacing={2}>
+                <Typography
+                  variant="h6"
+                  fontWeight="bold"
+                  sx={{ my: 2, textAlign: "center" }}
+                >
+                  各種アクション日時
+                </Typography>
+                <SimpleDataList data={actionDatetimes} />
+              </Stack>
+            </Paper>
+          </Grid>
         </Grid>
-      </Grid>
-    </Box>
+      </Box>
+      {changeHandlerDialog.element}
+    </>
   );
 }
diff --git a/src/pages/dashboard/receipt-issuing-order/hooks/useChangeHandlerDialog.tsx b/src/pages/dashboard/receipt-issuing-order/hooks/useChangeHandlerDialog.tsx
new file mode 100644
index 0000000..fee6aa6
--- /dev/null
+++ b/src/pages/dashboard/receipt-issuing-order/hooks/useChangeHandlerDialog.tsx
@@ -0,0 +1,144 @@
+import { yupResolver } from "@hookform/resolvers/yup";
+import {
+  Button,
+  Dialog,
+  DialogActions,
+  DialogContent,
+  DialogTitle,
+} from "@mui/material";
+import { Dictionary } from "@types";
+import {
+  Handler,
+  ReceiptIssuingOrder,
+  changeHandler,
+  getHandlers,
+} from "api/receipt-issuing-order";
+import { FormProvider } from "components/hook-form";
+import RHFSelect, {
+  SelectOptionProps,
+  makeOptions,
+} from "components/hook-form/RHFSelect";
+import useAPICall from "hooks/useAPICall";
+import useSnackbarCustom from "hooks/useSnackbarCustom";
+import { useEffect, useMemo, useState } from "react";
+import { useForm } from "react-hook-form";
+import * as Yup from "yup";
+
+type FormProps = {
+  handler_id: string;
+};
+
+export default function useChangeHandlerDialog(
+  order: ReceiptIssuingOrder | null,
+  onComplete?: VoidFunction
+) {
+  const [show, setShow] = useState(false);
+  const { success, error } = useSnackbarCustom();
+
+  const [handlers, setHandlers] = useState<Handler[] | null>(null);
+
+  const options: SelectOptionProps[] = useMemo(() => {
+    if (handlers === null) return [];
+    return handlers.map((ele) => ({
+      value: ele.id,
+      label: ele.name,
+    }));
+  }, [handlers]);
+
+  const form = useForm<FormProps>({
+    defaultValues: {
+      handler_id: "",
+    },
+    resolver: yupResolver(
+      Yup.object().shape({
+        handler_id: Yup.string().required("必須項目です"),
+      })
+    ),
+  });
+
+  const { callAPI: callGetHandlers } = useAPICall({
+    apiMethod: getHandlers,
+    backDrop: true,
+    onSuccess: ({ data }) => {
+      setHandlers(data.records);
+    },
+  });
+
+  const { callAPI: callChangeHandler } = useAPICall({
+    apiMethod: changeHandler,
+    backDrop: true,
+    onSuccess: () => {
+      success("変更しました");
+      setShow(false);
+      if (onComplete) {
+        onComplete();
+      }
+    },
+    onFailed: () => {
+      error("失敗しました");
+    },
+  });
+
+  const open = () => {
+    setShow(true);
+  };
+
+  const close = () => {
+    setShow(false);
+  };
+
+  const handleSubmit = (data: FormProps) => {
+    if (!order) return;
+    callChangeHandler({
+      id: order.id,
+      handler_id: data.handler_id,
+      timestamp: order.updated_at,
+    });
+  };
+
+  const element = (
+    <Dialog
+      open={show}
+      onClose={close}
+      PaperProps={{
+        sx: {
+          width: "50%",
+        },
+      }}
+    >
+      <DialogTitle>担当者変更</DialogTitle>
+
+      <FormProvider methods={form} onSubmit={form.handleSubmit(handleSubmit)}>
+        <DialogContent>
+          <RHFSelect name="handler_id" label="担当者" options={options} />
+        </DialogContent>
+
+        <DialogActions>
+          <Button onClick={close}>CANCEL</Button>
+          <Button type="submit">OK</Button>
+        </DialogActions>
+      </FormProvider>
+    </Dialog>
+  );
+
+  useEffect(() => {
+    setHandlers(null);
+    form.setValue("handler_id", "");
+    if (show) {
+      callGetHandlers({});
+    }
+  }, [show]);
+
+  return {
+    // param
+    show,
+
+    // Element
+    element,
+    // function
+
+    open,
+    close,
+    setShow,
+  };
+}