NOVELTY - A polymeric porous membrane (1) consists of a triple-layered structure having surface layer (a), surface layer (b), and macrovoid layer (3) provided between the surface layer (a) and the surface layer (b). The macrovoid layer is partition bonded with the surface layer (a) and the surface layer (b). The diameter of macrovoids (4) along the membrane plane direction is 10-300 mu m. The ratio of average hole diameter of macrovoids contained in surface layer (b) with respect to average hole diameter of macrovoids contained in the surface layer (a) side of macrovoid layer is 5-20000.    USE - Polymeric porous membrane is used as separator for battery and electrolytic capacitor, diaphragm of filter used for microfiltration, separation process, and dust collection process, substance-filling support material, and acoustic component protective film (all claimed).    ADVANTAGE - The polymeric porous membrane has excellent dimensional stability, and high porosity and strength.    DETAILED DESCRIPTION - A polymeric porous membrane consists of a triple-layered structure having surface layer (a), surface layer (b), and macrovoid layer provided between the surface layer (a) and the surface layer (b). The macrovoid layer is partition bonded with the surface layer (a) and the surface layer (b). The surface layer (a) and surface layer (b) enclose several macrovoids. The diameter of macrovoids along the membrane plane direction is 10-300 mu m. The ratio of average hole diameter of macrovoids contained in surface layer (b) with respect to average hole diameter of macrovoids contained in the surface layer (a) side of macrovoid layer is 5-20000. The ratio of diameter of macrovoids in the membrane plane direction with respect to average hole diameter of macrovoids contained in the surface layer (b) side is 1-2.    DESCRIPTION OF DRAWING(S) - The drawing shows the cross-sectional view of polymeric porous membrane along plane direction.    Polymeric porous membrane (1)    Macrovoid layer (3)    Macrovoids (4)