diff --git a/addons/account_voucher/account_voucher.py b/addons/account_voucher/account_voucher.py
index 541702dccb4..be2e61060a3 100644
--- a/addons/account_voucher/account_voucher.py
+++ b/addons/account_voucher/account_voucher.py
@@ -964,11 +964,11 @@ class account_bank_statement_line(osv.osv):
         return res
 
     def _check_amount(self, cr, uid, ids, context=None):
-        obj = self.browse(cr, uid, ids[0])
-        if obj.voucher_id:
-            if not (obj.amount == obj.voucher_id.amount):
-                return False
-            return True
+        for obj in self.browse(cr, uid, ids):
+            if obj.voucher_id:
+                if not (obj.amount == obj.voucher_id.amount):
+                    return False
+        return True
 
     _constraints = [
         (_check_amount, 'The amount of the voucher must be the same amount as the one on the statement line', ['statement_id']),