The present invention provides an adhesive film including a resin having a silsesquioxane in a side chain and a urethane bond in a main chain, together with a method for forming the same. The inventive adhesive film has excellent stretchability and strength, with the film surface having higher adhesion and thinner film thickness.本發明目的為提供一種伸縮性黏著膜,具有優異的伸縮性與強度,膜表面為高黏著性,且為薄膜;以及其形成方法。一種黏著性膜,其特徵為:含有側鏈具有倍半矽氧烷且主鏈具有胺甲酸乙酯鍵的樹脂。