NOVELTY - The stainless steel contains carbon (in mass%) (0.03 or less), chromium (16-30), nickel (7-40), titanium (2 or less), niobium (2 or less), molybdenum (7 or less) and tungsten (7 or less), and remainder of iron and unavoidable impurity. The Laves phase ((Fe, Cr)2(Ti, Nb, Mo, W) type) with a particle size of 0.3 microns or more exists in more than 1011 piece/m2 on the surface of stainless steel. The content of titanium, niobium, molybdenum, and tungsten satisfy specific relation.    USE - For polymer electrolyte fuel cell (claimed) used for motor vehicle, and electroconductive stainless-steel electrical component.    ADVANTAGE - The stainless steel has excellent corrosion resistance, and low contact resistance. The stainless steel provides fuel cell having excellent durability and electroconductivity, and is economical.    DETAILED DESCRIPTION - The stainless steel contains carbon (in mass%) (0.03 or less), chromium (16-30), nickel (7-40), titanium (2 or less), niobium (2 or less), molybdenum (7 or less) and tungsten (7 or less), and remainder of iron and unavoidable impurity. The Laves phase ((Fe, Cr)2(Ti, Nb, Mo, W) type) with a particle size of 0.3 microns or more exists in more than 1011 piece/m2 on the surface of stainless steel. The content of titanium, niobium, molybdenum, and tungsten satisfy relation: 2 (%Ti) + (%Nb) + (%Mo) + 0.5 (%W) greater than or equal to 1, where %Ti is Ti content (mass%), %Nb is Nb content (mass%), %Mo is Mo content (mass%), and %W is W content (mass%). The stainless steel further contains nitrogen (2 or less), silicon (3 or less), manganese (2.5 or less), and copper (5 or less). The polymer electrolyte fuel cell has solid polymer film, electrode, gaseous-diffusion layer, and a separator. The separator is stainless steel.    DESCRIPTION OF DRAWING(S) - The figure shows a perspective view of the polymer electrolyte fuel cell. (Drawing includes non-English language text)    Membrane-electrode assembly (1)    Gaseous-diffusion layers (2,3)    Separators (4,5)    Air flow path (6)    Hydrogen flow path (7)