PURPOSE: To enable separation of water from used wires within a used wire collection box, suppress rust generation, and prevent deterioration of the working environment at the time of throwing used wires, by installing a mesh member allowing passage of liquid in such a way as stretched below the collection box.

CONSTITUTION: A wire electrode 24 runs toward a lower guide 22 from a supply reel 26 via rollers 28, 30, 32, etc., to become a used wire 24a, and after passing a transport path 34, is deposited into a collection box 38 by an exhaust mechanism 36 to be collected there. The used wire 24a is wetted with water in the electrodischarge processing region, and part of water drops fall in a cover 34a for said transport path 34, and then sent to an inlet 38c at the top of the collection box 38 while pinched by a drive roller 36 and a press roller 36b. Water drops dripping from the used wire 24a fall under a mesh member 40 to come into a water receptacle 42 of drawout type so as to be capable of throwing to other places, if necessary, upon drawing a grip 44.