An eyeglass lens processing shape obtaining method for attaching a prescription lens having an edge thicker than an original lens and having refractive power to a rim of an eyeglass frame, in place of the original lens attached to the rim, the method includes: obtaining an outline of the original lens; obtaining an inner boundary of the rim on a surface of the original lens in a state where the original lens is attached to the rim; obtaining an external form processing shape of the prescription lens based on the outline of the lens; and obtaining a step processing shape of the prescription lens based on the inner boundary of the rim.