Abstract: A fuel cell comprising a stack including a stack including a plurality of cell units and a plurality of gas separators and at least one cooling plate, one of the gas separator and the cooling plate being interposed between adjacent cell units, the fuel cell being characterized in that; each gas separator and the cooling plate, respectively, have oxidant gas channels on one of surfaces that opposes to have contact with one of electrode surfaces of the cell unit to as to flow an oxidant gas in a direction vertical to a direction of a cooling air flowing through the cooling plate; each gas separator and the cooling plate, respectively, have fuel gas channels, a fuel-gas-supply inner manifold for taking in a fuel gas, and a fuel-gas-exhaust inner manifold for releasing the fuel gas having passed through the fuel gas channels on the other surface that opposes to have contact with the other electrode surface of the cell unit so as to flow the fuel gas in a direction parallel to the direction of the cooling air flow