A power-supply control device comprising: a voltage conversion unit (112; 211) that is adapted to step down a voltage at a battery to supply the stepped-down voltage to a first load, the battery includes a plurality of series-connected cells; a first opening and closing unit (RY1a, RY1b) that is adapted to open and close a supply path of first power from the battery to the voltage conversion unit (112; 211) and a second load; a battery control unit (114; 212; 311; 412) that is adapted to detect abnormality of the battery, to control opening and closing of the first opening and closing unit (RY1a, RY1b), and to be operated by second power supplied from the battery or third power supplied from the voltage conversion unit (112; 211), the second power being lower than the first power; characterised in that the power-supply control device further comprises: a second opening and closing unit (RY2a, RY2b) that is adapted to open and close a supply path of the second power from the battery to the battery control unit (114; 212; 311; 412), wherein the battery control unit (114; 212; 311; 412) is adapted to control opening and closing of the second opening and closing unit (RY2a, RY2b), wherein before the supply of the first power from the battery to the voltage conversion unit (112; 211) and the second load is started, the battery control unit (114; 212; 311; 412) is adapted to detect an abnormality of the battery when the first opening and closing unit (RY1a, RY1b) is opened and the second opening and closing unit (RY2a, RY2b) is closed, the battery control unit (114; 212; 311; 412) is adapted to close the first opening and closing unit (RY1a, RY1b) while opening the second opening and closing unit (RY2a, RY2b) when an abnormality of the battery is not detected, and the battery control unit (114; 212; 311; 412) is adapted to continuously open the first opening and closing unit (RY1a, RY1b) when an abnormality of the battery is detected. a voltage conversion unit (112; 211) that is adapted to step down a voltage at a battery to supply the stepped-down voltage to a first load, the battery includes a plurality of series-connected cells; a first opening and closing unit (RY1a, RY1b) that is adapted to open and close a supply path of first power from the battery to the voltage conversion unit (112; 211) and a second load; a battery control unit (114; 212; 311; 412) that is adapted to detect abnormality of the battery, to control opening and closing of the first opening and closing unit (RY1a, RY1b), and to be operated by second power supplied from the battery or third power supplied from the voltage conversion unit (112; 211), the second power being lower than the first power; a second opening and closing unit (RY2a, RY2b) that is adapted to open and close a supply path of the second power from the battery to the battery control unit (114; 212; 311; 412), wherein the battery control unit (114; 212; 311; 412) is adapted to control opening and closing of the second opening and closing unit (RY2a, RY2b), wherein before the supply of the first power from the battery to the voltage conversion unit (112; 211) and the second load is started, the battery control unit (114; 212; 311; 412) is adapted to detect an abnormality of the battery when the first opening and closing unit (RY1a, RY1b) is opened and the second opening and closing unit (RY2a, RY2b) is closed, the battery control unit (114; 212; 311; 412) is adapted to close the first opening and closing unit (RY1a, RY1b) while opening the second opening and closing unit (RY2a, RY2b) when an abnormality of the battery is not detected, and the battery control unit (114; 212; 311; 412) is adapted to continuously open the first opening and closing unit (RY1a, RY1b) when an abnormality of the battery is detected.