PURPOSE: To prevent generation of a scratch on the surface of a work owing to the removal of abrasive grains.

CONSTITUTION: In this dressing device, a voltage is applied between electrodes 25 and 26 by a power source device 27 in a grinding process, a weak current is fed to a grinding wheel 21, and a dressing is carried out in an electrytic in-process dressing method. A pushing member 30 squeezed to the working surface of the grinding wheel 21 at a specific pressure is provided between the electrode 26 and a work 22, and the surface of the grinding wheel 21 is rubbed by the pushing member 30 so as to remove the abrasive grains removable with a weak force, from the surface of the grinding wheel 21, before the dressed surface reaches to the work 22.