An extrusion molding method for improving the fluidity of a molding material in the die and significantly improving the productivity of the molded article of uniform thickness, and an extrusion molding apparatus adapted for smoothly carrying out the method and having an unsophisticated constructional arrangement, are disclosed.Molding is carried out while the die to which an extrusion orifice gap adjustment device is annexed is kept in resonant vibrations. The extrusion orifice gap adjustment device is annexed to a portion of the die constituting an extrusion orifice section, and molding is carried out while only the portion of the die is kept in resonant vibrations. The extrusion orifice gap adjustment device is annexed at a node of the resonant vibrations. The extrusion orifice of the die is provided at a position in register with a loop of the resonant vibrations, that is, at a position of the maximum effect of the vibrations, so that the frictional resistance between the molding material and the die surface in the vicinity of the extrusion orifice is reduced.