To extend a cycle lifetime of a secondary battery.

The secondary battery control device is provided with an input part 2 which accepts an input of a setting time of current supply time capable of continuous supply of a sub-battery 7 which discharges and supplies a back-up current to the devices 8, 9 and a control part 1 which measures a back-up time from the start of current supply to the stop of current supply of the sub-battery 7 to the devices 8, 9 and stops supply of current of the sub-battery 7, when the measured back-up time exceeds the setting time input by the input part 2.