Cemented tungsten carbide with nickel binder is often applied to the metal mold for electronic parts due to its non-magnetic feature. However, it is difficult to use conventional methods applied to metal molds made of steel for the surface finishing or modification of cemented tungsten carbides in some cases. The large-area EB irradiation for conventional cemented tungsten carbide with cobalt binder was studied in our previous papers. In this paper, surface finishing and modification of cemented tungsten carbide with nickel binder were investigated, and the effects of EB conditions on the surface characteristics were discussed. The experimental results indicated that the surface roughness decreased and the surface glossiness increased by the large-area EB irradiation. Also, the water repellency and the releasability of molded resin from the surface could be improved under proper EB conditions.