To uniformly and effectively utilize a grinding sheet by relatively reciprocating moving a grinding disc and a bar-shaped in one direction, relatively turning the grinding disc and the bar-shaped member by a prescribed turning radius without changing the direction of the grinding disc.

A motor for turning is driven, an eccentric shaft is rotated via a pulley, a transmission belt and a pulley, a disc on the upper end part of the eccentric shaft is rotated and a grinding disc 2 is turned and moved in a state that the grinding disc 2 is maintained to a fixed direction by prescribed eccentric amount via a bearing. By driving a slide motor 18, rotating a pinion 19 fitted on the tip of the shaft of the slide motor 18 and transmitting this rotational force to a rack 17 provided on the lower part of a rotary substrate, the grinding disc 2 is linearly moved to a bar-shaped member 4 and the end face of the bar-shaped member 4 is ground.