A request determining unit compares a battery temperature of a battery unit with a predetermined temperature management value, and produces a heating request or a cooling request when a temperature deviation of a predetermined threshold is present between them. A current direction determining unit determines, based on thermal reaction characteristics of the battery unit, in which one of a direction on a charge side and a direction on a discharge side a current is to be passed for responding to the heating request or the cooling request. A target current value determining unit determines a target current value related to the charge/discharge determined by the current direction determining unit. A current control unit produces a switching instruction for matching a battery current of the battery unit with the target current value provided from a selecting unit.