PURPOSE: To make a three-dimensional form machinable, by performing two- dimensional slides with a cross slides with a cross slide and a headstock, while turning a spindle, where a work body is set, round to the headstock and making a pair of machinig heads, fitted with a stretched wire electrode, free of parallel movements in a separate manner.

CONSTITUTION: A headstock 7 holding a spindle 8 to which a work body 19 is set and a table 3 mounted with this headstock are all possible to move in both Y and X directions, while the spindle 8 is turned round its axis together with the work body 19. A wire electrode 16 is displaced by movements in each independet parallel direction of machining heads 14 and 14' where the wire electrode is stretched over. In time of forming the work body 19 into a cone or a circular truncated cone, each of arms 13 and 13' attached to each of these machining heads 14 and 14' is slidden to some extent, setting a relative position of these machining heads 14 and 14' properly, and a specified angle corresponding to a profile to be machined is given to the electrode 16 whereby rotation in the spindle 8 and sliding motion in the table 2 are combined, thus the work is machined.