diff --git a/data/class/SC_CartSession.php b/data/class/SC_CartSession.php
index e79cb97240..8d09c25af1 100644
--- a/data/class/SC_CartSession.php
+++ b/data/class/SC_CartSession.php
@@ -371,7 +371,7 @@ public function setCartSession4getCartList($productTypeId, $key)
         $quantity = $this->cartSession[$productTypeId][$key]['quantity'];
         $incTax = SC_Helper_TaxRule_Ex::sfCalcIncTax($price,
             $this->cartSession[$productTypeId][$key]['productsClass']['product_id'],
-            $this->cartSession[$productTypeId][$key]['id'][0]);
+            $this->cartSession[$productTypeId][$key]['id']);
 
         $total = $incTax * $quantity;
 
@@ -638,7 +638,7 @@ public function checkProducts($productTypeId)
                         $this->setProductValue($arrItem['id'], 'quantity', $limit, $productTypeId);
                         $total_inctax = $limit * SC_Helper_TaxRule_Ex::sfCalcIncTax($arrItem['price'],
                             $product['product_id'],
-                            $arrItem['id'][0]);
+                            $arrItem['id']);
                         $this->setProductValue($arrItem['id'], 'total_inctax', $total_inctax, $productTypeId);
                         $tpl_message .= '※「' . $product['name'] . '」は販売制限(または在庫が不足)しております。';
                         $tpl_message .= "一度に数量{$limit}を超える購入はできません。\n";