Stainless steel excellent in corrosion resistance, ferritic stainless steel excellent in resistance to crevice corrosion and formability, and ferritic stainless steel excellent in resistance to crevice corrosion

The stainless steel of the first embodiment includes C: 0.001 to 0.02%, N: 0.001 to 0.02%, Si: 0.01 to 0.5%, Mn: 0.05 to 0.5%, P: 0.04% or less, S: 0.01% or less, Ni: more than 3% to 5%, Cr: 11 to 26%, and either one or both of Ti: 0.01 to 0.5% and Nb: 0.02 to 0.6%, and contains as the remainder, Fe and unavoidable impurities. The stainless steel of the second embodiment has an alloy composition different from those of the first and third embodiments and satisfies the formula (A): Cr+3Mo+6Ni≧23 and formula (B): Al/Nb≧10 and contains as the remainder, Fe and unavoidable impurities. The stainless steel of the third embodiment has an alloy composition different from those of the first and second embodiments and includes either one or both of Sn: 0.005 to 2% and Sb: 0.005 to 1% and contains as the remainder, Fe and unavoidable impurities.