A charge/discharge control circuit includes: an output terminal from which a cell-balance control signal is sent to each of the first and the second cell balance circuits; the first and the second voltage detection circuits; a control circuit configured to send the first and the second control signals in accordance with a detection signal received from at least one of the first and the second voltage detection circuits; and an output circuit configured to select one of a voltage of a power supply terminal, a voltage of an input terminal connected to each of a negative electrode of a first battery and a positive electrode of a second battery, and a voltage of a ground terminal in accordance with the first and second control signals, and send the selected voltage to the output terminal.