A lens frame, made from metal, retaining a light-emitting lens and a light-receiving lens is retained between a second mold and a third mold both of which are made from light-shielding resins. Anchors are formed by filling light-shielding resin for forming the third mold into fixing slots formed in an upper surface of the second mold and through holes formed in the lens frame. Since the lens frame is made from metal, thermal expansion of the lens frame is hardly caused by ambient temperature changes and self-heating. This causes little difference in the amount of change in difference between the lenses. Further, the lens frame is fixed with anchors between the second mold and the third mold. This suppresses the occurrence of sliding caused by difference in thermal expansion coefficient between the lens frame and the second and third molds.