A method for producing a weather strip including an extrusion molded extrusion molded portion, an injection molded portion which is formed by a molding device having a plurality of mold members and connects both ends of the extrusion molded portions in a straight line shape, a mounting base portion which is mounted on a circumferential edge of an opening of a body or a circumferential edge of an opening/closing member for opening and closing the opening, and a hollow sealing portion which protrudes from the mounting base portion, and is pressed against an opposite member when the opening/closing member for opening and closing the opening is closed.