Substantially cylindrical supporting units are formed at both sides of a lens. The supporting units are to adjust the separation distance between the lens and the surface of a substrate depending on the height dimension of a light emitting diode mounted on the substrate from the substrate face when the lens body is fixed to the substrate. A cylindrical convex part is formed at a part of the tip face of the supporting unit in a concentric fashion relative to the supporting unit, and a cylindrical positioning unit is formed at a part of the tip face of the convex part in a concentric fashion. The positioning unit functions as a member for positioning when the substrate and the lens body are fixed to each other.