A first wrist element is rotatably provided on the front end of a forearm base of a robot. A second wrist element is rotatably provided on the first wrist element. A welding torch is rotatably supported via a transmission mechanism. A wire feeder is disposed at a position other than a forearm. A torch cable is fitted to a slider with an intermediate fitting section. A slider can be pulled backward by returning a wire connected to a tension generator using a pulley. In place of the fitting section, an intermediate guiding section can be provided.