Fuel cell

A fuel cell comprises a catalyst layer and a gas diffusion layer. The gas diffusion layer comprises first section having surface A that comes in direct contact with anode-side (14) or cathode-side separator plate and second section having surface B that faces gas flow channel (15) of anode-side or cathode-side separator plate. The porosity of first section is lower than that of second section and second section protrudes into gas flow channel. A fuel cell comprises a polymer electrolyte membrane; an anode and a cathode sandwiching the polymer electrolyte membrane; and an anode-side separator plate and a cathode-side separator plate sandwiching the anode and the cathode. The anode-side separator plate has a gas flow channel for supplying a fuel gas to the anode. The cathode-side separator plate has a gas flow channel for supplying an oxidant gas to the cathode. Each of the anode and the cathode comprises a catalyst layer and a gas diffusion layer. The gas diffusion layer comprises a first section having a surface A that comes in direct contact with the anode-side or cathode-side separator plate and a second section having a surface B that faces the gas flow channel of the anode-side or cathode-side separator plate. The porosity of the first section is lower than that of the second section and the second section protrudes into the gas flow channel.