An annular insert (4) is arranged in the optical component molding cavity of a mold to surround an outer periphery of raw material resin in a direction in which the resin is distributed in the cavity to limit the distribution of the raw material resin and define an outer profile of a lens (L). With this arrangement, it is only necessary to provide raw material resin only by a quantity equal to the volume of the region surrounded by the molding surfaces of upper and lower mold inserts (14, 24) and the inner peripheral edge of the annular insert (4) of the mold, so that the required volume of the raw material resin can be reduced. Since the pressure is preserved at the outer periphery of the distributed resin by the presence of the annular insert (4), the residual strain of the resin is minimized to prevent generation of sink mark, thereby providing excellent optical characteristics on the lens (L).