A battery voltage monitoring device for efficiently equalizing cell voltages of a plurality of battery cells connected in series through a direct charge transfer between mutually distant battery cells. The device includes a charge-transfer circuit configured to perform a direct charge transfer from a first battery cell to a second battery cell that is fifth or higher adjacent to the first battery cell. This can eliminate charge-transfer losses that would occur during sequential charge transfers between adjacent battery cells, which leads to an efficient charge transfer between mutually distant battery cells.