Light emitted from a light source such as LED and reflected by a fingertip is guided by a cover member onto a light receiving surface of an imaging element. A second resin part is provided that is in contact with the cover member and a resin molded part sealing the imaging element. The reflected light guided by the cover member is made to reach the light receiving surface via the second resin part and the resin molded part, traveling along a path spaced apart from an air layer.