Abstract: A centering method for holding a lens, which has been molded using a molding die, between a pair of holders of a bell clamp system, and centering the outer circumference of the lens, this method including: a first step of using a planar part of the lens, formed using a molding surface of a molding die, to position the lens with respect to a guidance part of a positioning member configured to enable the positioning of the lens, and a second step of holding the lens between one and the other holders and another holder so that the optical axis of the lens positioned in the first step aligns with the central axis of the one holder. It is possible to prevent the optical surface of the workpiece lens and an antireflective film from being scratched when centering an aspherical lens or a spherical lens as the workpiece lens.