diff --git a/app/Services/InspectionService.php b/app/Services/InspectionService.php
index 3f142c77..45c9e2af 100644
--- a/app/Services/InspectionService.php
+++ b/app/Services/InspectionService.php
@@ -218,6 +218,10 @@ public function update(int $id, array $data)
             throw new NotFoundHttpException(__('error.not_found'));
         }
 
+        if ($inspection->status === Inspection::STATUS_COMPLETED) {
+            throw new BadRequestHttpException(__('error.inspection.cannot_modify_completed'));
+        }
+
         $beforeData = $inspection->toArray();
 
         return DB::transaction(function () use ($inspection, $data, $userId, $beforeData) {
diff --git a/lang/ko/error.php b/lang/ko/error.php
index c914ef12..e5ef71c2 100644
--- a/lang/ko/error.php
+++ b/lang/ko/error.php
@@ -456,6 +456,7 @@
     'inspection' => [
         'not_found' => '검사를 찾을 수 없습니다.',
         'cannot_delete_completed' => '완료된 검사는 삭제할 수 없습니다.',
+        'cannot_modify_completed' => '완료된 검사는 수정할 수 없습니다.',
         'already_completed' => '이미 완료된 검사입니다.',
     ],