PURPOSE: To make it possible to machine a complicated workpiece with the use of a low cost facility, by coupling grindstones by means of a resilient material, and by jetting resilient particles to which conductivity is given, together with electrolyte so that the machining voltage or current is detected by a detector to control the voltage or current.

CONSTITUTION: Electrolyte having been compressed by a pump 4 is jetted from an internal nozzle 3 in a nozzle assembly 1 so that electrolyte 8 containing resilient particles 7 is sucked from a tank 6 into an opening 6 which is in a vacuum condition due to the jetting, and is jetted onto a workpiece 9 from the tip 2 of the nozzle. These resilient particles 7 are formed of abrasive grain such as SiC, diamond or the like which are solidified by a resilient material such as natural rubber or synthetic rubber such as PB silicone or the like. The abrasive grain is formed of a conductive material alone, a mixture of conductive and non- conductive materials, or the resilient material containing metal particles. With this arrangement, the resilient particles 7 in which a part of the abrasive grain 10 is projected from the outer surface of the resilient material 11, grind the workpiece while they make familiar with the concave and convex surface of the workpiece 9 which is the subjected to electrolytic machining with the electrolyte 8. Further, a power source 12 detects the voltage between the nozzle and the workpiece to control power for machining, and detects electrical current to control machining current.