diff --git a/addons/purchase/models/stock.py b/addons/purchase/models/stock.py
index 4edd90aafbb..62d9a1d1b30 100644
--- a/addons/purchase/models/stock.py
+++ b/addons/purchase/models/stock.py
@@ -48,7 +48,7 @@ class StockMove(models.Model):
     def _get_price_unit(self):
         """ Returns the unit price for the move"""
         self.ensure_one()
-        if self.purchase_line_id:
+        if self.purchase_line_id and self.product_id.id == self.purchase_line_id.product_id.id:
             line = self.purchase_line_id
             order = line.order_id
             price_unit = line.price_unit