To surely obtain effects when a local part of a metallic member is reinforced by a TIG filler welding method.

By using an electrode 4 having a spherical face at the tip, a peripheral wall of a concave part 2 is cast to a spherical shape coaxially with that of the electrode 4. The concave part 2 is welded while a filler 5 is positioned on a rear side with respect to the proceeding direction of the electrode 4, and then the concave part 2 is welded again while the filler 5 is positioned on a front side with respect to the proceeding direction of the electrode 4. In this case, the electrode is vibrated at a given amplitude. Furthermore, a minimum gap between the electrode 4 and the filler 5, and the supply angle of the filler 5 are limited.