diff --git a/addons/purchase/models/account_invoice.py b/addons/purchase/models/account_invoice.py
index 9c1cf48312c..873921b322f 100644
--- a/addons/purchase/models/account_invoice.py
+++ b/addons/purchase/models/account_invoice.py
@@ -144,6 +144,7 @@ class AccountInvoice(models.Model):
                     valuation_price_unit = i_line.product_id.uom_id._compute_price(i_line.product_id.standard_price, i_line.uom_id)
                     if i_line.product_id.cost_method != 'standard' and i_line.purchase_line_id:
                         #for average/fifo/lifo costing method, fetch real cost price from incomming moves
+                        valuation_price_unit = i_line.purchase_line_id.product_uom._compute_price(i_line.purchase_line_id.price_unit, i_line.uom_id)
                         stock_move_obj = self.env['stock.move']
                         valuation_stock_move = stock_move_obj.search([('purchase_line_id', '=', i_line.purchase_line_id.id), ('state', '=', 'done')])
                         if valuation_stock_move: