PURPOSE: To make it possible to safely press a whitestone stick against a CBN grindstone by providing a stick guide coming into contact with the side of the stick detachably attached to an automatic feed device.

CONSTITUTION: In dressing a CBN grindstone 1, a feeding motor 14 with a reduction gear is driven to rotate a ball screw 9, and a saddle 7 is thereby lowered under the guidance of a guide bar 6 to make a tool holder 23 lower through a pushing rod 18 and an adapther 19. A stick 2 held by the holder 23 is lowered as it slides along stick guides 24, 30, and pressed on the peripheral grinding face of the CBN grindstone 1 for its dressing. In this case, the stick 2 is pressed on the rear stick guide 24 by an elastically pressing tool 27, which damps the vibration of the stick 2.