PURPOSE: To carry out the grinding of a cutter while removing a resin or the like attached on the surface of the cutter efficiently for a short time by moving a rotary brush sliding along the surface on condition that the brush is contacted to the surface of the disk-form cutter.

CONSTITUTION: A cutter 5 is loaded on a turntable 3 on condition that a holding rod 21 is penetrated through an installing hole 25 at the center of the turntable 25, a regulating tool 19 is attached to the holding rod 21, and the cutter 5 is fixed to the turntable 3 on condition that both rotation centers are coincided. Then, a control device is operated, and a brush 6 is moved from the periphery to the rotation center on condition that the lower part of the brush is contacted to the side of the set cutter 5, while a motor is driven to rotate the rotary brush 6. In this case, since the position where the lower surface of the rotary brush 6 is contacted to the side of the cutter 5 is separated from the rotation center, a rotation force is given to the cutter 5 by the rotation of the brush 6. By the rotations of the cutter 5 and the brush 6, the resin attached to the side of the disk-form cutter 5 is washed and removed, and the side of the cutter 5 can be ground.