To obtain a product reduced in strain by injection molding and to also obtain a part having molding preciseness and dimensional accuracy fitted to required capacity.

In a retractor housing, a transmission easing, a lock housing or a lock cover, a part is produced from a long fiber reinforced plastic in which fibers are taken by pultrusion. As a plastic to be used, polypropylene is pref. and a long fiber material is selected from a glass fiber, a metal fiber and a polymer fiber.