A fuel cell device with a compound power supply is disclosed, which comprises a bipolar fuel cell board and an auxiliary power supply. The bipolar fuel cell board includes at least one fuel cell unit. The auxiliary power supply is disposed on the bipolar fuel cell board and/or on an intermediate substrate sandwiched within the fuel cell device, and is connected to the fuel cell units. Stable power is output due to the combination of power from the fuel cell units and the auxiliary power supply.