To solve a conventional problem in which burn through, weld bead defects, etc., are liable to occur, as a result of gradual increase in the welding current average value through change in fusion characteristics, which are caused by oxidation advanced on a wire surface with the lapse of time after the sealed package of the welding wire is opened, in the AC pulsed arc welding of aluminum alloys, for example.

In this output control method for AC pulsed arc welding, the welding current average value Ida during the welding is detected and, a ratio of electrode minus current, which is a ratio of an electrode minus current taken in the welding current average value, is varied by the increase/decrease of the electrode minus current Ins, in the manner that the average value Ida becomes nearly equal to a predetermined current set value Is.