The performance of electrically conductive CVD (called EC-CVD) diamond thick film possessing a high thermal diffusivity has been examined as an electrode for fine electrical discharge machining (EDM). The results indicate a possibility of zero wear in EDM as compared to copper and copper-tungsten (Cu-W) electrodes. It is particularly significant at short pulse EDM conditions, where the EC-CVD diamond electrodes showed increased machining efficiency and a remarkably low wear. In EDM of tungsten carbide, a very low electrode wear ratio of 0.3% was realized with the EC-CVD diamond electrode. Zero wear EDM could be achieved even for sharp V-shapes with included angles of 15 and 30° with V-shaped EC-CVD diamond electrodes. Thermal FEM analysis to examine the relation between the thermal diffusivity and temperature distribution at short pulse duration indicated lowest temperature on EC-CVD diamond electrode surface.