A gas tungsten arc welding method using flux is provided to weld without the welding defect including the incomplete penetration and surface under fill by supplying a welding wire after coating the surface of the base material with the flux. A gas tungsten arc welding method performing a step for facing with base materials(12) each other; a step for coating with the deep flux(19) the penetration in the surface of a welding joint; a step for completing welding process through one welding work by supplying a welding wire(18) at the front of an electrode(14) of a WC torch received electric power.
