diff --git a/htdocs/compta/facture/class/facture.class.php b/htdocs/compta/facture/class/facture.class.php
index fa03d8527b0..a8f80335496 100644
--- a/htdocs/compta/facture/class/facture.class.php
+++ b/htdocs/compta/facture/class/facture.class.php
@@ -3553,7 +3553,7 @@ class FactureLigne
 			$sql.= ",total_localtax1=".price2num($this->total_localtax1)."";
 			$sql.= ",total_localtax2=".price2num($this->total_localtax2)."";
 		}
-		$sql.= " , fk_product_fournisseur_price='".$this->fk_fournprice."'";
+		$sql.= " , fk_product_fournisseur_price=".(! empty($this->fk_fournprice)?"'".$this->db->escape($this->fk_fournprice)."'":"null");
 		$sql.= " , buy_price_ht='".price2num($this->pa_ht)."'";
 		$sql.= ",fk_parent_line=".($this->fk_parent_line>0?$this->fk_parent_line:"null");
 		if (! empty($this->rang)) $sql.= ", rang=".$this->rang;