diff --git a/src/pages/dashboard/use-summary/custom/hello-techno/list.tsx b/src/pages/dashboard/use-summary/custom/hello-techno/list.tsx
index 0c03231..5a5ce15 100644
--- a/src/pages/dashboard/use-summary/custom/hello-techno/list.tsx
+++ b/src/pages/dashboard/use-summary/custom/hello-techno/list.tsx
@@ -15,27 +15,25 @@ import { ApiId } from "api";
 import {
   UseSummary,
   getUseSummaries,
-  getUseSummaryYYYYMMs,
 } from "api/custom/hello-techno/use-summary";
 import { getFullUrl } from "api/url";
 import { PageID, TabID } from "codes/page";
 import { FormProvider } from "components/hook-form";
 import RHFDatePicker from "components/hook-form/RHFDatePicker";
-import RHFSelect, { SelectOptionProps } from "components/hook-form/RHFSelect";
 import { TableHeadCustom } from "components/table";
 import { HeadLabelProps } from "components/table/TableHeadCustom";
 import { SearchConditionContextProvider } from "contexts/SearchConditionContext";
+import { addMonths, endOfMonth, startOfMonth } from "date-fns";
 import useAPICall from "hooks/useAPICall";
 import useDashboard from "hooks/useDashBoard";
 import useNavigateCustom from "hooks/useNavigateCustom";
 import useSearchConditionContext from "hooks/useSearchConditionContext";
 import useTable, { UseTableReturn } from "hooks/useTable";
 import { SearchParam } from "pages/dashboard/receipt-issuing-order/custom/hello-techno/list";
-import { useEffect, useMemo, useState } from "react";
+import { useEffect, useMemo } from "react";
 import { useForm } from "react-hook-form";
 import { getPath } from "routes/path";
-import { sprintf } from "sprintf-js";
-import { dateParse, formatDateStr } from "utils/datetime";
+import { dateParse, formatDateStr, now } from "utils/datetime";
 
 export default function UseSummaryList() {
   const { setHeaderTitle, setTabs } = useDashboard(
@@ -127,8 +125,14 @@ function SearchBox({ table }: CommonProps) {
   // 初期値設定
   useEffect(() => {
     if (initialized) {
-      form.setValue("date_from", dateParse(get("date_from")));
-      form.setValue("date_to", dateParse(get("date_to")));
+      const lastMonth = addMonths(now(), -1);
+      const defaultDateFrom = startOfMonth(lastMonth);
+      const defaultDateTo = endOfMonth(lastMonth);
+      form.setValue(
+        "date_from",
+        dateParse(get("date_from")) ?? defaultDateFrom
+      );
+      form.setValue("date_to", dateParse(get("date_to")) ?? defaultDateTo);
     }
   }, [initialized]);