Stainless steels for high-purity gases which are superior in non-dusting characteristics required at the time of welding, corrosion resistance and non-catalytic property and which can be widely utilized in the manufacturing process of semiconductors, liquid crystal displays or the like. The austenitic stainless steels of the present invention are characterized by having decreased Mn, Al, Si and O contents. The austenitic stainless steels meet the non-dusting characteristics which are required at the time of welding. In addition, corrosion resistance, abrasion resistance and machinability are improved. The ferritic and the duplex stainless steels of the present invention are characterized in that they can readily form thereon a Cr oxide layer when subjected to oxidation treatment. The ferritic and two-phase stainless steels are superior in corrosion resistance to corrosive gases, and contain non-catalytic property against chemically-unstable gases.