A charge/discharge control circuit has cell balance detecting circuits that detect that a cell voltage has reached a prescribed voltage; memory circuits that have stored therein the first cell among a plurality of cells that reached a prescribed voltage; bypass circuits that are connected parallel to the cells, and have switching means for bypassing the currents flowing into the aforementioned cells upon charging; and control circuits for controlling the switching means. The control circuits control the switching means on the basis of the first cell stored in the memory circuits, and maintain the ON/OFF states of the switching means for the duration from start to finish of the charging that is subsequent to the charging for which the first cell was stored in the memory circuits.