A first wrist element 11 is rotatably provided around an axis line A, on the front end of a forearm base 10 of a robot 1. A second wrist element 12 is rotatably provided around a second axis line B, on the first wrist element 11. A welding torch 2 is rotatably supported around a line C via a transmission mechanism 13. The third axis line C is disposed approximately perpendicularly to the axis line B and is remote from the axis line A by a predetermined distance. A wire feeder 4 is disposed at a position (on a mounting table 8, an upper arm, or a rotating body) other than a forearm. A torch cable 3 is fitted to a slider 6b that is movably fitted along a direction approximately parallel with the first axis line A, with an intermediate fitting section 3a. A slider 6b can be pulled backward by returning a wire 81 connected to a tension generator 80 using a pulley 82. In place of the fitting section 3a, an intermediate guiding section can be provided, and the torch cable 3 can be movably guided along a direction approximately parallel with the first axis line A. With this arrangement, an excessive looseness or tension of the torch cable and an occurrence of interference with the wire feeder can be prevented.