Provided is a separator including a porous substrate having a plurality of pores, and a porous coating layer provided on at least one surface of the porous substrate and formed from a mixture of plural inorganic particles and a binder polymer, in which the binder polymer is a result of a curing reaction of an acryl-based copolymer and an isocyanate-based crosslinking agent, and the acryl-based copolymer is a copolymer including (a) a first monomer unit with a tertiary amine group, (b) a second monomer unit with at least one functional group selected from an amine group other than a tertiary amine group, an amide group, a cyano group, and an imide group, (c) a third monomer unit of (meth)acrylate with a carboxyl group, (d) a fourth monomer unit of (meth)acrylate with a hydroxyl group, and (e) a fifth monomer unit of (meth)acrylate with an alkyl group having 1 to 14 carbon atoms, and an electrochemical device comprising the same.