Abstract: A method for producing a sealing member for a battery includes integrally insert-molding a gasket on a peripheral edge of a metal sealing plate. The gasket is molded on the peripheral edge of the metal sealing plate by inserting the metal sealing plate between the female and male molds, the female mold having a concave surface conforming to the upper surface of the metal sealing plate and provided with a magnet or vacuum suction mouth to attract the metal sealing plate in its center, and the male mold having a surface conforming to the lower surface of the metal sealing plate, then injecting a molten resin into a cavity formed between the female mold and the male mold while pressing the female and male molds against each other by an elastic member.