A charging apparatus for charging a cell group, in which a plurality of secondary cells are connected in series, by supplying a charging current Ic to the secondary cells is provided with an overcharge protection circuit including discharge route circuits 34 provided to each of the secondary cells and adapted to cause the secondary cells to discharge during charging by connecting the secondary cells to the discharge route circuits based on cell voltages Vb of the secondary cells or to stop discharging by cutting off the secondary cells from the discharge route circuits; and a charger controller for continuing charging while reducing the charging current Ic until the discharge of the secondary cell having started discharging to the discharge route circuit is stopped when the discharge of any one of the secondary cells to the discharge route circuit is started by the overcharge protection circuit.