diff --git a/shop/cartupdate.php b/shop/cartupdate.php
index 1b2e4afc6..ad0887b6f 100644
--- a/shop/cartupdate.php
+++ b/shop/cartupdate.php
@@ -74,7 +74,9 @@ if($act == "buy")
                             and ct_status = '쇼핑'
                             and ct_select = '1' ";
                 $sum = sql_fetch($sql);
-                $sum_qty = $sum['cnt'];
+                // $sum['cnt'] 가 null 일때 재고 반영이 제대로 안되는 오류 수정 (그누위즈님,210614)
+                // $sum_qty = $sum['cnt'];
+                $sum_qty = is_int($sum['cnt']) ? $sum['cnt'] : 0;
 
                 // 재고 구함
                 $ct_qty = $row['ct_qty'];