A battery control unit includes a switching unit and a control unit. The switching unit is provided for each of a plurality of batteries connected to in series to each other, and switches a connection state in which the corresponding battery is discharged and a non-connection state in which the corresponding battery is not discharged. The control unit switches the battery to the non-connection state in order from the battery whose remaining dischargeable capacity reaches a predetermined value. Further, the control unit switches all the batteries to the connection state after the remaining dischargeable capacity of all the batteries reaches the predetermined value, and then switch the battery to the non-connection state in order from the battery determined to reach a discharge termination state.