Fuel cell

A fuel cell (1) including a proton-conducting solid electrolyte membrane (2), an oxidant electrode (3) provided on one side of the solid electrolyte membrane, and a fuel electrode (4) provided on the other side of the solid electrolyte membrane characterized in that at least one of the oxidant electrode and the fuel electrode includes a polarizing means (7) for electrochemically polarizing at least one of the oxidant electrode and the fuel electrode for oxidizing, or reducing, a fuel, or an oxidant, passing through the solid electrolyte membrane.