PURPOSE: To uniformize a lot of random holes by polishing and uniforming each hole diameter in a way of adding such an initial job that reciprocatively moves a work clamping table along a guide rail.

CONSTITUTION: A work pieced through with a lot of prepared holes is set to a work clamping table 3 at the upper part of a multihole simultaneous grinding attachment, and each fine edge of lots of taper wires 2 is pierced through a prepared hole 9' of this work 9, winding it on a wire winding device 7, stretching across the frame. The work clamping table 3 is reciprocated to the taper wire 2, thereby smoothing its insertional motion. Next, the taper wire 2 moves as being wound up by the wire winding device 7, and the work clamping table 3 is clamped to a rocking table 8 rocking in the same direction with this moving direction, the prepared hole 9' of the work 9 is polished for finishing by means of thickening the taper wire 2 diametrally with this rocking motion and movement. Thus, a lot of prepared holes 9' can be uniformly pol ished at the same time.