A fuel cell unit is provided with a fuel cell for electric power generation, a mixing tank housing a mixture of fuel and exhaust from the fuel cell, a fuel tank housing the fuel, a pump delivering the mixture and air to the fuel cell, a casing housing the fuel cell, the pump and at least one of the fuel tank and the mixing tank and a partition partitioning an interior of the casing into a first compartment housing the fuel cell and a second compartment. The partition is provided with first, second and third flow paths. The first flow path connects the mixing tank to the fuel cell. The second flow path connects the fuel cell to the pump. The third flow path connects the pump to the mixing tank.