A power-supply control device for battery having a plurality of cells connected in series has a voltage conversion unit that steps down a voltage at the battery to supply the stepped-down voltage to a first load, a first opening and closing unit that opens and closes a supply path of first power from the battery to the voltage conversion unit and a second load, a battery control unit that detects abnormality of the battery, controls opening and closing of the first opening and closing unit, and is operated by second power supplied from the battery or third power supplied from the voltage conversion unit, the second power being lower than the first power, and a second opening and closing unit that opens and closes a supply path of the second power from the battery to the battery control unit.