After start of pre-air-conditioning, when a preset set condition is satisfied, an in-vehicle terminal transmits information regarding a vehicle state and a screen display command for selection between continuation and termination of the pre-air-conditioning to a mobile terminal. The mobile terminal receives the screen display command and displays a notification indicating the vehicle state and a selection button for selection between the continuation and the termination of the pre-air-conditioning on a screen. After obtaining the vehicle state, the user selects whether to continue or terminate the pre-air-conditioning. In this manner, pre-air-conditioning suitable for each individual user can be performed.