Abstract: A fuel cell has a gas diffusion layer (15A, 15C) provided on at least one surface side of a polymer electrolyte membrane (12). The polymer electrolyte membrane is structured with a conductive carbon sheet. Fluid flow passages (16A, 16C) are formed on the surface of the gas diffusion layer (15A, 15C) contacting a separator (21A, 21C). The roughness of the surface of the gas diffusion layer (15A, 15C) provided with the fluid flow passage is smaller than the roughness of its surface contacting the catalyst layer (14A, 14C). Thus, it becomes possible to achieve a further improvement in power generation performance, and to suppress a reduction in durability.

Abstract: In a fuel cell of the present invention, a gas diffusion layer (15A, 15C) provided on at least one surface side of a polymer electrolyte membrane (12) is structured with a conductive carbon sheet. Fluid flow passages (16A, 16C) are formed on the surface of the gas diffusion layer (15A, 15C) contacting on a separator (21A, 21C). The roughness of the surface of the gas diffusion layer (15A, 15C) provided with the fluid flow passage is set to be smaller than the roughness of its surface contacting on the catalyst layer (14A, 14C). Thus, it becomes possible to achieve a further improvement in power generation performance, and to suppress a reduction in durability.