diff --git a/frontend/src/pages/TaskListPage.tsx b/frontend/src/pages/TaskListPage.tsx
index 51493a9..d8ac976 100644
--- a/frontend/src/pages/TaskListPage.tsx
+++ b/frontend/src/pages/TaskListPage.tsx
@@ -44,7 +44,7 @@ import { TOBUY_ERRORS } from '../constants/errorMessages';
 const EMPTY_TOBUY: Omit<ToBuy, 'tobuyId' | 'stuffId'> & { stuffId: number | null, category: string } & { newAddition: boolean } = {
   stuffId: null,
   stuffName: '',
-  amount: 0,
+  amount: 1,
   shop: '',
   category: '',
   newAddition: false,
@@ -174,6 +174,11 @@ const TaskListPage: React.FC = () => {
       if (newToBuy.newAddition) {
         newToBuy.stuffId = null;
       }
+      if (isNaN(newToBuy.amount)) {
+        console.log('数量が正しくありません．');
+        return;
+      }
+
       console.log(newToBuy)
       await toBuyApi.addToBuy(newToBuy);
       setOpenDialog(false); // ダイアログを閉じる
@@ -191,6 +196,11 @@ const TaskListPage: React.FC = () => {
    */
    const handleUpdateTask = async () => {
     try {
+      if (isNaN(selectedEditingTask.amount)) {
+        console.log('数量が正しくありません．');
+        return;
+      }
+
       console.log(selectedEditingTask)
       await toBuyApi.updateToBuy(selectedEditingTask);
       setOpenAmountDialog(false); // ダイアログを閉じる
@@ -299,7 +309,7 @@ const TaskListPage: React.FC = () => {
 
                   <IconButton
                     edge="end"
-                    sx={{ marginLeft: 3 }}
+                    sx={{ marginRight: 0, marginLeft: 0 }}
                     aria-label="delete"
                     onClick={() => handleDeleteTask(tobuy.tobuyId)}
                   >
@@ -411,7 +421,7 @@ const TaskListPage: React.FC = () => {
               onChange={(e) => {
                 const value = e.target.value;
                 const parsedValue = parseInt(value, 10); // 数値に変換
-                if (!isNaN(parsedValue) && parsedValue >= 0) { //負数除外
+                if (/*!isNaN(parsedValue) && */ isNaN(parsedValue) || parsedValue >= 1) { //負数除外
                   setNewToBuy({ ...newToBuy, amount: parsedValue }); // number型で保存
                 }
               }}
@@ -517,7 +527,7 @@ const TaskListPage: React.FC = () => {
               onChange={(e) => {
                 const value = e.target.value;
                 const parsedValue = parseInt(value, 10); // 数値に変換
-                if (!isNaN(parsedValue) && parsedValue >= 0) { //負数除外
+                if (/*!isNaN(parsedValue) && */ isNaN(parsedValue) || parsedValue >= 1) { //負数除外
                   setSelectedEditingTask({ ...selectedEditingTask, amount: parsedValue }); // number型で保存
                 }
               }}