A fuel cell module includes a cell unit including an electrolyte membrane, a cathode disposed on one face of the electrolyte membrane, and an anode disposed on the other face of the electrolyte membrane, and a water reservoir which stores water produced at the cathode. The water reservoir includes an opening formed in a region other than the cathode of the cell unit, and a projection projecting from the opening to an anode side. The water covering a cathode surface of a fuel cell is reduced.