A vehicular thermo-control device adjusts a temperature of a battery. The device has a primary system through which cooling water circulates, and a secondary system through which a refrigerant circulates. The primary system has a heat exchanger which performs heat exchange between the battery and the cooling water, and a heat exchanger which performs heat exchange between the cooling water and an ambient air. The secondary system is a refrigerating cycle. Both heat exchangers on a high temperature side and a low temperature side of the refrigerating cycle are thermally coupled with the primary system. Only one heat exchanger provides heat exchange with the ambient air. The pump of the primary system can switch circulating direction of the cooling water. A controller controls devices to perform cooling and heating operation.