A battery control circuit includes a voltage detection circuit for measuring voltages of electric cells, balancing circuits for balancing the voltages or SOCs of the electric cells, a signal input/output circuit for communicating with the outside, a power supply circuit having two modes: a normal mode and a low consumption mode, and a time management circuit. It receives a signal containing a period of time until the shift of the power supply circuit from the normal mode to the low consumption mode, and stores it in the time management circuit. If a command from the outside has not been sent for a predetermined period of time or when an operation stop command has been sent from the outside, the time management circuit causes the power supply circuit to continuously operate in the normal mode. Then, the battery control circuit monitors an operation continuation period in the normal mode, and causes the power supply circuit to shift to the low consumption mode when the operation continuation period matches the stored period of time.