A separator for an electrochemical device of the present invention includes a porous film including: a filler; an organic binder; and at least one resin selected from resin A that has a melting point of 80 to 140° C. and resin B that absorbs a non-aqueous electrolyte and swells upon heating and whose swelling degree increases with increasing temperature, and the filler contains boehmite having a secondary particle structure in which primary particles are connected.