A control device is provided in a vehicle to control an air conditioning apparatus and thereby to control ventilation and air conditioning of a passenger room of the vehicle. A mobile device communicates with the control device in a parked state of the vehicle to selectively control a first device, which performs ventilation of the passenger room, and a second device, which performs air conditioning of the passenger room, of the air conditioning apparatus in such a manner that at least one of the first device and the second device is selectively operated upon reception of a corresponding operational instruction from the operating device.