A charging apparatus includes a battery pack, which includes a cell voltage detection unit outputting a signal if a detected cell voltage is not smaller than V1, and a temperature sensor detecting a temperature of the battery pack; and a charger, which includes a charging control circuit and a pack voltage detection unit detecting a voltage across two terminals of the battery pack. If the detected temperature from the temperature sensor exceeds 0.degree. C., the charging control circuit switches to a constant voltage charging when the signal from the cell voltage detection unit is received; and if otherwise, the charging control unit switches to the constant voltage charging when receiving the signal or the detected pack voltage exceeds V2, whichever occurs first.