To use a thermoplastic elastomer as the resin material of a plate with a resin frame.

A molding 7 of the thermoplastic elastomer, which is extruded from a molding die 6, is cooled to 100°C or below. Next, a surface adherent to a lip and the plate 1 is heated so that the temperature TL of the lip of the molding 7, the temperature TA of the surface adherent to the plate 1 of the molding 7, and the temperature TO of the press surface of the molding 7 are in the relationships of TO<TL<TA and TA≥200°C. Then the press surface is pressed so that the molding 7 is adhered to the peripheral fringe part of the plate 1 through the adherent surface.