In order to improve safety while suppressing a decrease in efficiency of an equalizing process between a plurality of cells, controller executes an equalizing process between a plurality of cells by controlling a plurality of discharge circuits based on voltages of the plurality of cells measured by voltage measurement unit. Anomaly determination circuit determines whether or not the voltage of each of cells measured by voltage measurement unit is within a normal range. Controller includes, for each first cycle, a first discharge suspension period during which the voltages of the plurality of cells are measured without an influence of the equalizing process during execution of the equalizing process between the plurality of cells and includes, for each second cycle longer than the first cycle, a second discharge suspension period during which a determination result according to anomaly determination circuit is fixed.