In an air amount control for controlling an air amount to be blown into a vehicle compartment, a water temperature control map in which the air amount is set based on a water temperature of cooling water for the vehicle is stored, and the air amount is determined based on control characteristics of the water temperature control map. The water temperature control map is learned and changed based on a set air amount, and the air amount to be blown into the vehicle compartment is determined based on the learned water temperature control map in a case where the set air amount is changed by a passenger and the water temperature is in a predetermined range.