An electrochemical device having excellent safety at a high temperature is provided by using a separator for an electrochemical device, which is made of a porous film including a first separator layer and a second separator layer. The first separator layer includes, as a main ingredient, at least one kind of resin selected from the group consisting of resin A that has a melting point in a range of 80° C. to 130° C., and resin B that absorbs a nonaqueous electrolyte and swells due to heating and whose swelling degree is increased as the temperature rises, the second separator layer includes, as a main ingredient, a filler that has a heat-resistant temperature of not lower than 150° C., and at least one of the first separator layer and the second separator layer includes flakes.