PURPOSE: To prevent extreme deflected thickness, and also, to easily manufacture the cabinet by hollow-forming two pieces of cosmetic cabinets by a blow molding method or a rotational molding method, etc., in a cavity formed by a split mold.

CONSTITUTION: By using two pieces of mating dies A, A' having the die face of the same or a symmetrical shape, two pieces of mating cosmetic cabinets 1, 1 are hollow-molded by one of a blow molding method or a rotational molding method, etc. After a formed part is parted from its mating dies A, A' two pieces of face washing and cosmetic cabinets 1, 1 are obtained simultaneously by dividing it into two from the center face 4. As a result, extreme deflected thickness can be prevented, and even in the case a highly protruded bulge part like a bank exists, in the top face and the base part, there is no remarkable difference in thickness, and sufficient strength can be displayed substantially, as well. Also, at the time of dividing into two, a die run generated by blow molding, etc., can be eliminated simultaneously at the time by division by executing the division by eliminating prescribed width centering around the parting face 4, and the workability is satisfactory.