A lens is provided which is configured so that the dimensional accuracy of the lens surface can be evaluated easily and accurately, and the control of the accuracy of the lens can be easily performed. The lens comprises a lens effective part having lens surfaces formed around an optical axis as the center and an edge part in a doughnut shape as viewed in a plan view, which is extended along the outer periphery of the lens effective part. The edge part and the lens effective part are molded simultaneously, and annular indices around the optical axis as the center, with which the dimensional accuracy of the lens surfaces can be detected, are formed on both the surfaces of the edge part.