To recover only a filter element as a waste and make it compact so that its disposal is made easy when a filter device is discarded by assembling the filter element which is structured of a filter medium packed between end plates with a liquid supply aperture into a pressure-resistant casing through which a liquid passes.

The filter element 11 is structured of a pleated filter paper 14 which is bonded liquid-tightly with an adhesive 15 between a pair of end plates 12, 13. Further a mouthpiece 18 to be connected to a high pressure hose 17 for sending a fabrication liquid under pressure from an electric discharge machining device is attached to one of the end plates 12, 13. In addition, the filter element 11 is loaded in a pressure-resistant casing 16, and at the same time, a top lid 19 is disposed on the casing 16 in such a manner that the mouthpiece 18 just out of a hole 20. The top lid 19 is clamped to the casing 16 with a band 21 with a U cross section. Therefore, when the filter device is replaced, the top lid 19 is opened by removing the band 21 and the filter element 11 has only to be removed from the casing 16.