A lens shape measuring apparatus is disclosed, which is capable of identifying a size of an outer-diameter shape of a lens fixing jig by using a measuring element also used for measuring a lend shape. This lens shape measuring apparatus comprising: a lens fixing jig installed in an eyeglass lens to be processed to clamp the eyeglass lens; a lens rotation shaft for clamping and rotating the lens to be processed; a measuring element abutted on a refracting surface of the lens clamped by the lens rotation shaft; a measuring element position switching mechanism for controlling rotation of the measuring element around a rotation shaft roughly parallel to the lens rotation shaft; and a measuring unit for measuring a moving distance of the measuring element in a direction roughly parallel to the lens rotation shaft. This lens shape measuring apparatus also comprises arithmetic control means for moving a tip of the measuring element relatively in the direction roughly parallel to the lens rotation shaft, measuring a distance from a measuring reference position of the measuring element to an abutting position of the same by the measuring unit, and identifying a shape of the lens fixing jig based on a result of the measurement.