A fuel cell detection device according to the present invention includes: a cell block formed with a plurality of cells serially connected to each other; a voltage detection element for detecting voltages of the cells within the cell block; and another voltage detection element for detecting a voltage of the operating power source of the voltage detection element, where the operating power source of the voltage detection element is supplied from a voltage of the inside or both ends of the cell block, and the operating power source of another voltage detection element is supplied from a voltage of the outside of the cell block, the operating power source of another voltage detection element being less variable than the operating power source of the voltage detection element.