Abstract: A robot system, including a robot having a wrist mechanism including a flange that is rotatable about a rotation axis, a welding torch fixed to the flange by a torch bracket, and a welding sensor that is fixed with respect to the welding torch and that detects a weld line, where the welding sensor is disposed at a position between the flange and a fixed position at which the welding torch is fixed to the torch bracket, the welding sensor is capable of scanning a laser beam, and the welding torch includes a tubular torch body that is arranged so as to protrude toward a distal end side than the fixed position, and makes a wire protrude from a distal end of the tubular torch body by the tubular torch body curved at least twice.