Provided is a voltage equalization device (200) for a power accumulation device (300) equipped with batteries (20) each formed by connecting a plurality of secondary cells, power converters (30) arranged to correspond to the batteries (20), and control units (40) for controlling the power converters (30), wherein the batteries (20) are connected in parallel via each of the power converters (30). The voltage equalization device (200) is equipped with a check unit and a voltage adjustment unit. The check unit acquires battery information relating to the charge/discharge state of the respective batteries (20) and determines whether to execute a voltage adjustment according to the battery information for each of the batteries (20). If the check unit has determined to execute the voltage adjustment, the voltage adjustment unit generates an offset instruction for adjusting the charge/discharge state and outputs the offset instruction to the control unit (40) of the power converter (30) corresponding to the battery (20).