Cell balance control device and cell balance controlling method

A cell balance control device includes a battery monitor unit (2, 3-1 ¼ 3-n), a cell balance unit (4), and an ECU (7), and equalizes serially connected chargeable battery cells (11-1 ¼ 11-n) in a battery loaded into a vehicle. The battery monitor unit (2, 3-1 ¼ 3-n) detects the voltage of each battery cell (11-1¼11-n). The cell balance unit (4) equalizes the voltages of the plurality of battery cells (11-1 ¼ 11-n) based on the voltage of each battery cell (11-1 ¼ 11-n) detected by the battery monitor unit (2, 3-1 ¼ 3-n) . At least one of the times when an idling stop state of the vehicle starts, when the charging operation of the battery starts, and when the charging operation of the battery terminates triggers the ECU (7) allowing the cell balance unit (4) to equalize the voltage of the plurality of battery cells.