Wire electrochemical micromachining (WEMM) is proposed as a new method of micro fabrication in this paper. Effects of the diameter of wire electrode on the machining accuracy of WEMM are investigated theoretically. In situ fabrication of wire electrode is proposed in this study to fabricate micro meter scale wire electrode. The tungsten wire electrode with the diameter of 5μm is electrochemically in situ fabricated for the production of micro structures. Micro blades with the slit width of 20μm and micro sharp-angles structure with the radius of 1μm are machined experimentally.