Provided are a cell balance device for protecting a switch circuit from an overcurrent flow. The cell balance device includes: a plurality of electric accumulator connection terminals each connected to one of a node and two terminals of electric accumulators connected in series; a voltage hold device connection terminal connected to a voltage hold device; a plurality of first switch circuits provided between the plurality of electric accumulator connection terminals and the voltage hold device; a control circuit for controlling ON/OFF of the plurality of first switch circuits based on a synchronization signal; and an overcurrent detection circuit for detecting an overcurrent flowing through each of the plurality of first switch circuits.