diff --git a/app/Http/Middleware/ManagementMiddleware.php b/app/Http/Middleware/ManagementMiddleware.php
index fba3d05..b15c07c 100644
--- a/app/Http/Middleware/ManagementMiddleware.php
+++ b/app/Http/Middleware/ManagementMiddleware.php
@@ -33,7 +33,10 @@ class ManagementMiddleware
         }
 
         // 運営元コードの正当性検証のため、DBで存在確認
-        $management = DB::table('management')->where('management_code', $managementCode)->first();
+        $management = DB::table('management')
+            ->where('management_code', $managementCode)
+            ->where('valid_flag', 1)  // 有効フラグが1の場合のみ
+            ->first();
 
         if (!$management) {
             // 不正アクセス防止のため、エラーログでシステム例外を記録