PURPOSE: To easily produce a hot-dip Zn-Al alloy coated steel wire having excellent corrosion resistance in a single plating operation by using a flux of specified composition consisting essentially of ZnCl2.

CONSTITUTION: A long-sized steel wire (a) continuously rewound from a swift 1 at a high speed is passed through a degreasing tank 2 to remove the oil deposit, pickled 3 and then washed 4 with water. The washed wire is passed through a tank 5 contg. a flux 10 consisting of 70-80wt.% ZnCl2 10-20wt.% SnCl2 and 5-20wt.% of an alkali metal chloride such as KCl or an alkalineearth metal chloride and then dried 6. The fluxed wire is passed through a hot-dip Zn-Al alloy coating bath 11, plated pulled up as the plated wire (a) by a sinker roll 7, and the amt. of the coating is finely adjusted to an appropriate amt. at a partitioned throttle part 8.