A welding torch includes an inner tube of a helically wound wire to define a passage for a welding wire, a conduit in which the inner tube is inserted, the conduit having a curved portion, a torch body including a tip portion and a nozzle, a torch holder having a gas supplying member that supplies a shield gas into a space between the inner tube and the conduit, a feed unit provided upstream of the torch holder to feed the welding wire forward to or backward from the inner tube, and a sealing mechanism for preventing a reverse flow of the shield gas to the feed unit. A gap is defined between the adjacent wires of the inner tube allowing the shield gas to flow therethrough, and permitting wear debris generated by abrasion of the welding wire sliding in the inner tube to be ejected out from the nozzle.