When a coolant controlled to have a constant target temperature is used regardless of a traveling condition of a vehicle, a fuel efficiency of the vehicle may be reduced. Therefore, a VCU 1 predicts the output of an internal combustion engine in a future prediction period on the basis of position information of the vehicle acquired from a positioning unit, traffic information related to a route to a destination, and internal combustion engine control information, determines a target coolant temperature which is the target temperature of the coolant for cooling the internal combustion engine on the basis of the predicted output of the internal combustion engine, sets the change timing for changing the temperature of the coolant to the target coolant temperature on the basis of the predicted output of the internal combustion engine, and controls the operation of the coolant temperature change unit for changing the temperature of the coolant at the change timing so as to reach the target coolant temperature on the basis of the predicted output of the internal combustion engine.