To perform exact drilling processing by exactly setting the position of a screw hole without putting a mark on a lens surface in advance on the basis of a lens gage and a dummy lens in a drilling method to perform working processing for the screw hole or an outer peripheral groove or the like on the lens of rimless spectacles.

The lens gage 16 is accurately clamped on the surface of a table which moves in front-and-rear and right-and-left directions and also whose inclination angle is adjusted via lens stops 12a, 12b..., and is detached to set the dummy lens 19 on the surface of the table by the lens stops 12a, 12b..., then the position and the inclination angle of the table are adjusted so that a guard pin 24 attached to a drill chuck 23 can be fit in the screw hole 20 and the outer peripheral groove 21 provided on the dummy lens 19. Thereafter, the dummy lens 19 is removed to set the lens having specified shape, and the guard pin 24 is removed to attach a drill 27 or an end mill 28, and then the working processing for the screw hole and the outer peripheral groove or the like is performed on the lens.