A polymer electrolyte fuel cell comprises a separator plate having a gas channel
for supplying an oxidant gas or a fuel gas to an electrode, said separator plate
comprising a metal plate, a conductive film formed on the surface of the metal
plate, and a diffused layer resulting from diffusion of a material of the conductive
film formed between the metal plate and the conductive film. The fuel cell produces
stable output free from corrosion or dissolution of the metal plate even in a long-term operation.
