Abstract: An electrode wire for wire electrodischarge machining includes a core made of copper or copper alloy, a pure zinc layer formed by hot-dip galvanizing the core, and a relatively thin copper-zinc alloy layer formed by mutual thermal diffusion across the interface between the pure zinc layer and the core and having a zinc concentration gradient. The electrode wire is not cracked during its production. The thickness of the copper-zinc alloy layer, the gradient of zinc concentration, and the thickness of the outermost pure zinc layer can be controlled by selecting the dipping time and the temperature of the hot-dip galvanizing bath as appropriate. By blowing a non-oxidizing gas from a bath surface zinc purifying and wiping device disposed above the bath surface through which the core emerges from the hot-dip galvanizing bath, the pure zinc bath surface is kept exposed and runs and uneven thickness of the galvanizing layer are prevented.