The present invention relates to a separator comprising a coating layer and a battery using the same, the separator having improved adhesive force to an electrode, thereby minimizing the rate of thickness change. More specifically, the present invention relates to a separator having a coating layer on one or both surfaces of a base film, the coating layer comprising an acrylic-based copolymer having a glass transition temperature of less than or equal to 80° C. and an inorganic particle, so as to have improved adhesive force and heat resistance, thereby being applicable in electrochemical batteries of various sizes and having excellent thermal stability and dimensional stability.