PURPOSE: To enhance the working accuracy by installing an electric-discharge machining wire along a guide member so as to be slidable.

CONSTITUTION: An electrode-discharge machining wire W is installed along a guide member 2 so as to be slidable. By moving a work R toward the wire W, the surface of the work R is machined along the guide member 2. Since the surface of the work R can be machined by the electric-discharge machining wire W along the guide member 2, when the wire W is fed to the guide member 2 by a prescribed amount at a time, always a new cutting member can be supplied, so that working accuracy can be enhanced.