A fuel cell comprises a unit cell having a membrane-like electrode unit including an electrolyte membrane, a fuel electrode consisting essentially of a catalyst layer and a diffusion layer, which are formed in the order mentioned on one surface of the electrolyte membrane, and an air electrode consisting essentially of a catalyst layer and a diffusion layer, which are formed in the order mentioned on the other surface of the electrolyte membrane. The diffusion layer of at least the fuel electrode includes a carbon paper prepared by laminating carbon fibers, and a specified water repellent polymer is arranged to cover the surface of the carbon fiber of the carbon paper or is loaded in the clearance among the carbon fibers.