<p>A cell balancing device comprises: an assembled battery in which a plurality of battery stacks formed by connecting a plurality of battery cells in series are connected in series; a plurality of primary coils connected in parallel with the assembled battery; a plurality of secondary coils connected in parallel with the respective battery cells; and a switching circuit connected to each of the primary coils in series. The secondary coils connected to the battery cells constituting a battery stack are transformer-coupled to one primary coil. The primary coils are each transformer-coupled to different secondary coils. This constitutes a transformer-coupled circuit capable of balancing the cell voltages of the battery cells in each of the battery stacks by switching the switching circuits connected to the primary coils.</p>
