PURPOSE: To prevent the inclusion of voids and to reduce production cost by applying the pushing force directed to a male mold-base to a laminate by the concave surface formed at the cylindrical inner surface of an outer mold fitted onto the cylindrical part of the male mold and being corresponding to one part of the curved surface portion continued to the cylindrical part of the male mold.

CONSTITUTION: An outer mold 15 has the cylindrical inner surface corresponding to the cylindrical part 11 of a male mold 10, and then the concave surface 17 corresponding to one part of curved surface part 12 continued from the cylindrical part 11 is continuously formed on the upper part of the cylindrical inner surface of the outer mold. Accordingly, when the outer mold 15 is fitted onto the laminate 14, the laminate 14 on the periphery of the cylindrical part 11 is pushed by the cylindrical inner surface 16 of the outer mold 15, and simultaneously, the pushing force directed to a base 13 is applied to one part of the laminate 14 on the curved surface portion 12 by said concave surface 17, whereby the laminate containing a top part is stretched. By this process, the effect of distributing the resin uniformly is obtained, while exhausting the voids. Then, the cost for producing the mold is reduced compared with the female mold covering totally the male mold.