diff --git a/backend/app/Http/Controllers/Api/FatherRelationsController.php b/backend/app/Http/Controllers/Api/FatherRelationsController.php
index e2b3485d..b8232976 100644
--- a/backend/app/Http/Controllers/Api/FatherRelationsController.php
+++ b/backend/app/Http/Controllers/Api/FatherRelationsController.php
@@ -39,7 +39,7 @@ class FatherRelationsController extends Controller {
                 FatherRelation::create($create);
             }
             else {
-                FatherRelation::where('child_id', $child->id)->update($create);
+                return ['status_code' => 400, 'error_messages' => ['すでに追加されました']];
             }
         } catch (\Throwable $e) {
             // 失敗