PURPOSE: To shape a conductive grindstone with a metal as the binder in a high efficiency and yet to reduce the consumption of a truing element by providing an insulation means which insulates electrically the truing element from a rotation device rotating the conductive grindstone and a load dispatching means which feeds an electric power to the truing element.

CONSTITUTION: A truing element 1 is rotated by a rotation mechanism 11 and fed toward the action face of a conductive grindstone (a) by a feeding mechanism 24. So, the truing element 1 is non-elastically brought into contact while rotating with the action face of the conductive grindstone (a). A work liquid is fed from a work liquid feeding means 4 toward both contact parts between the truing element performing the movement like this and the conductive grindstone, in addition to the power which applies such a voltage as the grindstone side becoming plus in average being fed respectively further. So, the action face of the conductive grindstone simultaneously receives an electric discharging action, electrolytic action and a polishing action. Consequently, the conductive grindstone with a metal as the binder can be shaped with high efficiency.