As a conventional problem, welding on surface-treated material, such as a zinc-coated steel plate, considerably generates air holes including blowholes and also generates lots of spatters. Present invention provides a method of controlling arc welding performed in a manner that a short-circuit period, in which a short circuit is generated between a welding wire and an object to be welded, and an arc period, in which an arc is generated after release of the short circuit, are repeated alternately. According to the method, welding current is increased from an arc-regeneration-before current to a first welding current at a detection of release of the short circuit such that an increase gradient of the welding current becomes not less than 750A/msec. This suppresses generation of air holes and spatters in welding work on a surface-treated material, such as a zinc-coated steel plate.