To provide a torch for the plasma arc welding to perform the high- speed plasma welding with large current by providing a third nozzle between a first nozzle and a second nozzle with their axes coincided with each other to increase the critical current for generation of the series arc.

A third nozzle 4 is formed so that its tip part is tapered, and a small gap is demarcated between a connection nozzle member 20b to constitute a first nozzle 2 and a tip side tapered surface of a flange part 20d of a nozzle body 20c which is not brought into close contact with the connection nozzle member. The inert gas such as pure Ar and pure He is fed to the third nozzle 4 using a torch in which the third nozzle 4 is arranged between the first nozzle 2 and the second nozzle 3, the high-speed inert gas flow layer is formed on the surface of the nozzle body 20c to constitute the first nozzle 2 opposite to the material to be welded to surely prevent generation the series arc.