diff --git a/addons/stock/wizard/stock_invoice_onshipping.py b/addons/stock/wizard/stock_invoice_onshipping.py
index f479c416101..4dc037e3879 100644
--- a/addons/stock/wizard/stock_invoice_onshipping.py
+++ b/addons/stock/wizard/stock_invoice_onshipping.py
@@ -30,9 +30,9 @@ class stock_invoice_onshipping(osv.osv_memory):
             context = {}
         stock =  self.pool.get('stock.picking')
         stock_browse = stock.browse(cr, uid, context.get('active_id'))
-        if stock_browse.sale_id:
+        if stock_browse.type == 'out':
             type_inv = 'out'
-        elif stock_browse.purchase_id:
+        elif stock_browse.type == 'in':
             type_inv = 'in'
         user = self.pool.get('res.users').browse(cr, uid, uid, context=context)
         company_id = context.get('company_id', user.company_id.id)