diff --git a/addons/stock_account/models/account_invoice.py b/addons/stock_account/models/account_invoice.py
index 343d6539edb..c046c927553 100644
--- a/addons/stock_account/models/account_invoice.py
+++ b/addons/stock_account/models/account_invoice.py
@@ -44,6 +44,8 @@ class AccountInvoiceLine(models.Model):
 
     def _get_anglo_saxon_price_unit(self):
         self.ensure_one()
+        if not self.product_id:
+            return self.price_unit
         return self.product_id._get_anglo_saxon_price_unit(uom=self.uom_id)
 
     def _get_price(self, company_currency, price_unit):