Ferrite stainless steel exhibiting excellent corrosion resistance and strength in weld zones, and TIG-welded structure

Provided are: a ferrite stainless steel that exhibits excellent weld-zone strength and excellent weld-zone corrosion resistance, particularly with respect to crevice corrosion, even if an argon-gas shield is not used during TIG welding; and a structure comprising said steel. In an ordinarily-corrosive environment, the corrosion resistance of a ferrite stainless steel containing prescribed amounts of constituents can be increased by using constituent mass percentages that satisfy relation 1. In a more corrosive environment, a welded structure that resists crevice corrosion can be produced by not only having the relationship between the constituents of the steel satisfy relation 1 but also having the relationship between the thickness of the steel sheet and the length of the weld bead exposed on the back surface satisfy relation 2. Weld strength can also be improved by having the amounts of niobium and vanadium satisfy relation 3, resulting in a welded structure exhibiting high weld strength. (Relation 1) Si + 2.5Al + 3Ti ≤ 1.50 (Relation 2) 0 < Wb/2t ≤ 1.50 (t being the thickness of the material being welded and Wb being the length of the weld bead exposed on the back surface) (Relation 3) Nb×V ≥ 0.01