According one embodiment, a fuel cell includes an electromotive section, a fuel tank, a mixing tank in which a fuel supplied from the fuel tank is mixed with water and an aqueous fuel solution to be supplied to the electromotive section is formed, an anode line through which the fuel is circulated between the electromotive section and the mixing tank, an air supply section which supplies air to the electromotive section, and a cathode line through which water obtained by condensing steam delivered from the electromotive section is guided to the mixing tank. The mixing tank has a water inlet, which is connected to the cathode line, extends at an angle to a vertical direction, and produces convection currents in the mixing tank, and a fuel inlet, which is connected to the fuel supply line and situated above the water inlet with respect to the vertical direction.