A porous film which is produced using a resin composition containing an ultra-high-molecular-weight polyolefin and a polyolefin wax having a weight average molecular weight of 3000 or less, in which the number of branches per 1000 carbon atoms that constitute the main chain of the polyolefin wax is 15 or less; a porous film which is produced using a resin composition containing an ultra-high-molecular-weight polyolefin and a polyolefin wax having a weight average molecular weight of 3000 or less, and which does not substantially contain a component that melts at a temperature of 60° C. or lower; a laminated porous film which comprises one of the porous films and a heat-resistance porous layer laminated on at least one surface of the porous film; and a separator for batteries, which comprises the porous film or the laminated porous film.