An adhesive composition includes0 an acryl copolymer having a carboxyl group, and a silane compound represented by Formula 1 or 2, thereby it is possible to exhibit excellent initial adhesiveness and adhesive durability under severe conditions, and prevent the substrate from being torn due to a decrease in adhesiveness by water applied thereto, and the adhesive from remaining on the substrate during peeling-off the adhesive layer, as well as after drying, the adhesive layer may exhibit favorable adhesiveness again, thus being used for re-bonding.