Application of a polyimide porous membrane having a three dimensional homogeneous structure to a photopolymer filter for semiconductors was examined. When polymer solution was passed through the polyimide porous membrane, there was no change in the molecular weight of the nonpolar polystyrene, but the high molecular weight molecules of the polar ArF model photopolymer T001 were selectively removed. Smaller pores and greater specific surface area in the polyimide porous membrane improve the adsorption efficiency, and the high molecular weight polar polymer removal property was promoted. Filtering photopolymers with the polyimide porous membrane suppressed the increase in defects that occurs with aging.