A managing structure, for an umbilical member for a work tool of a robot, capable of stabilizing the motion of the umbilical member during the operation of a wrist of the robot and making the work of modifying the system of the robot easier. The umbilical member is introduced into an opening formed at the back of a base of a forearm. The umbilical member extends through a hollow portion of a speed reducer and is drawn from a first opening formed on the side of a first wrist element. A cable for welding current and a tube for supplying shield gas, constituting the umbilical member, are directly connected to a welding torch rotatable about a third axis. A welding wire is guided and fed by a feed roller of a wire feeder and, then, is connected to the welding wire with the cable and the tube. The feed roller is driven by a motor contained within the first wrist element.