PURPOSE: To enable the application of wire cut electric discharge machining even if there are a hole with closed bottom and surrounding hindrance by making a small diameter and flexible electrode wire freely afloat between a feed part and a recovery part, and forming the wire to a desired shape for use as a machining electrode.

CONSTITUTION: A very small diameter and flexible electrode wire 11 is fed from between a drive roller 14 and a feed trailing roller 15 on the rotation of said roller 14, and recovered from between a recovery trailing roller 16 and said roller 14 at the same speed, thereafter being kept afloat between a feed part 12 and a recovery part 13. In this state, the electrode wire 11 tends to have rigidity for maintaining the shape thereof on inertia when transfer speed becomes higher, and to keep an initial state. Consequently, a guide block 19 is placed on the outside or the inside of the wire 11 for the formation thereof to a desired shape. The wire 11 so shaped is used and moved along the external surface of a workpiece for electric discharge machining. It becomes thereby possible to apply wire cut electric discharge machining, even if there are a hole with closed bottom and surrounding hindrance.