PURPOSE: To facilitate positioning of a nozzle on a machining table by providing a positioning pin which fixes a nozzle and protrudes from the tip hole of the nozzle, when it is fixed, further positions an insulator inserted in a corresponding pin hole at the time of electric discharge machining.

CONSTITUTION: A nozzle machining electrode 1 is used for an electric discharge machine and mounted on its machining head H. On the other hand, a nozzle fixing tool 5, in which a new or used nozzle (a) being a workpiece is fixed, is placed on a machining table T, and positioning of the nozzle (a) on the machining table T is performed by a positioning pin 9 and a pin hole 3 on the side of the nozzle machining electrode 1 corresponding to this positioning pin 9.