To precisely align a spectacle lens with a lens holder efficiently at low cost in a short time.

A lens meter 5 photographs the spectacle lens of a working object. An image processor 6 binarizes a photographed image, extracts a feature parameter of an individual pattern included in a binarized image, extracts the pattern with the feature parameter fit to a prescribed condition as a concealed mark formed preliminarily in the spectacle lens, finds a reference position, based on a position of the concealed mark, and finds an angle deviation of the spectacle lens. A host computer 9 angle-corrects a lay-out data corresponding to the spectacle lens of the working object, in response to the angle deviation, and finds the working center position based on the corrected lay-out data.