PURPOSE: To provide a molding method for preventing the thickness of a material from increasing at the corner part of a cup at the time of molding a cup shaped part through forward extrusion.

CONSTITUTION: An annular recessed part 41 is provided at the corner part between an outer wall part and the bottom part of a cup shaped stock 40, when the outer wall part of the cup shaped stock 40 is extrusion-molded forward, the increase of the thickness of the material by the flow of the material in molding time is canceled by the recessed part 41 to prevent the increase of the thickness of the material from being generated at this corner part.