To provide a charge controller for battery pack that equalizes the voltage of each cell even if the voltage of a capacitor changes.

The charge controller 1 for battery pack includes: a battery pack 10, where four cells 11A-11D are connected in series; a capacitor 20, MOS transistors 21 and 22; a step-down regulator 23; switches 24A-24D; cell voltage detectors 25A-25D; sample and hold circuits 26A-26D; a current detector 27; and a controller 35, which detects a plurality of voltage values and current values, about each of cells 11A-11D, by the sample and hold circuits 26A-26D and the current detector 27, and gets a voltage, where the amount of voltage drop by internal resistance is eliminated, as a corrective cell voltage, and extracts the lowest value of the corrective cell voltages as the lowest voltage, and charges the capacitor 20 by the battery pack 10, when this lowest voltage is at or under a predetermined value, and charges the cell 11 of the lowest voltage from the capacitor 20.

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