An arc welding robot having a welding wire conduit which has a bend radius above a certain level and arranged so that disadvantageous stress is not applied to the conduit by the motion of the robot arm. A conduit for a welding wire is inserted through a hole of a robot pedestal from the rear side of the robot, is supported by a second support member arranged on the pedestal, extends near the front side of a rotating body of the robot, and is supported by a first support member on the upper part of the rotating body while having a required minimum bend radius. The conduit after passing through the first support member is introduced to the rear side of the upper arm and is connected to a connector at the rear side of a wire feeder while having the required minimum radius, whereby the conduit presents a generally S-shape.