A separator may include (A) a porous substrate having pores, and (B) a porous coating layer formed on at least one surface of the porous substrate and made from a mixture of inorganic particles and a binder polymer, and the binder polymer may contain a copolymer of (a) a first monomer unit with at least one of an amine group and an amide group at a side chain, and (b) a second monomer unit of (meth)acrylate with an alkyl group having 1 to 14 carbon atoms. The porous coating layer of the separator may have a high packing density, thereby easily forming a thin film battery without hindering safety, and may have good adhesive strength with the porous substrate, thereby preventing detachment of the inorganic particles in the porous coating layer during assembly of an electrochemical device.