diff --git a/backend/app/Http/Controllers/Api/ChildrenController.php b/backend/app/Http/Controllers/Api/ChildrenController.php
index f61f12f9..b7ff45f9 100644
--- a/backend/app/Http/Controllers/Api/ChildrenController.php
+++ b/backend/app/Http/Controllers/Api/ChildrenController.php
@@ -42,7 +42,7 @@ class ChildrenController extends Controller {
             return ['status_code' => 400, 'error_messages' => ['既に使用されている電話番号です。']];
         }
 
-        $token = bin2hex(random_bytes(16));
+        $token = bin2hex(random_bytes(8));
         $create = [
             'type' => 0,
             'tel' => $r->tel,
@@ -126,7 +126,7 @@ class ChildrenController extends Controller {
             return ['status_code' => 400, 'error_messages' => ['電話番号が未登録です。入力した情報を確認してください。']];
         }
 
-        $token = bin2hex(random_bytes(16));
+        $token = bin2hex(random_bytes(8));
         $create = [
             'type' => 1,
             'child_id' => $result->id,
diff --git a/backend/app/Http/Controllers/Api/FathersController.php b/backend/app/Http/Controllers/Api/FathersController.php
index c862118e..4fceb07e 100644
--- a/backend/app/Http/Controllers/Api/FathersController.php
+++ b/backend/app/Http/Controllers/Api/FathersController.php
@@ -43,7 +43,7 @@ class FathersController extends Controller {
             return ['status_code' => 400, 'error_messages' => ['メールアドレスが未登録です。入力した情報を確認してください。']];
         }
 
-        $token = bin2hex(random_bytes(16));
+        $token = bin2hex(random_bytes(8));
         $create = [
             'type' => 1,
             'father_id' => $result->id,
@@ -92,7 +92,7 @@ class FathersController extends Controller {
             return ['status_code' => 400, 'error_messages' => ['入力したメールアドレスは既に登録済みです。同じメールアドレスは使用できません。']];
         }
         else {
-            $token = bin2hex(random_bytes(16));
+            $token = bin2hex(random_bytes(8));
             $create = ['email' => $r->email, 'token' => $token, 'ttl' => date('Y-m-d H:i:s', time()+28800)];
 
             try {