To remove a spatter deposited in a welding torch easily and steadily.

At the time of removing a spatter deposited in the interior of a welding torch 1, compressed air is supplied into a compressed air supply pipe 23, the inlet of a flow direction changeover valve 24 is changed-over to supply compressed air to the welding torch 1, then compressed air is injected into a nozzle 6 from a plurality of orifices arranged at the sealed gas injection part 5 of the welding torch 1, and thus a deposited spatter is blown out of the nozzle 6 and removed.