When an optical element 1 is primarily molded in a primary cavity between a movable-side metal die of a primary-molding metal die and a primary fixed-side metal die, a rotation regulation portion is formed to the optical element. When an adjacent member is molded in a secondary cavity between the movable-side metal die in which the optical element is held and the secondary fixed-side metal die by the secondary-molding metal die, after mold opening between the movable-side metal die of the primary-molding metal die and the primary fixed-side metal die, the optical element is regulated from slipping in rotation directions about a center axis of the optical element, by a concave-convex fit engagement portion at a joint portion between the rotation regulation portion of the optical element and a molding surface of the movable-side metal die.
