Abstract: A TIG welding apparatus comprises a welding current supply means for supplying an electric current, a shield gas supply means for supplying shield gases, a tungsten electrode connected to the welding current supply means, a welding torch disposed coaxially around the tungsten electrode and provided with inner and outer double gas shields having gas jetting nozzles through which the gases are jetted, a plurality of wires to be fed to a portion at which the gases are jetted through the gas jetting nozzles, a wire feeding means, and a heating means connected to the wires, except at least one wire, for heating the wires.