diff --git a/account_payment_sale/models/sale_order.py b/account_payment_sale/models/sale_order.py
index e96b3cd3b..d8ed2722f 100644
--- a/account_payment_sale/models/sale_order.py
+++ b/account_payment_sale/models/sale_order.py
@@ -45,6 +45,6 @@ class SaleOrder(models.Model):
         """Copy bank partner from sale order to invoice"""
         vals = super(SaleOrder, self)._prepare_invoice(order, lines)
         if order.payment_mode_id:
-            vals['payment_mode_id'] = order.payment_mode_id.id,
+            vals['payment_mode_id'] = order.payment_mode_id.id
             vals['partner_bank_id'] = order.payment_mode_id.bank_id.id
         return vals