To surely confirm the presence or absence of passengers in a car before staring an automatic recovering operation to be executed after an earthquake.

Sound generated in the car 1 is collected by a microphone 4 provided in the car 1 before the automatic recovering operation to be executed after the earthquake. A reference value corresponding to sound when there are no passengers in the car 1 is decided based on the sound collected by the microphone 4 before the automatic recovering operation. By comparing the sound collected by the microphone 4 with the decided reference value, the presence or absence of passengers in the car 1 is decided. When it is decided that there are no passengers in the car 1, the automatic recovering operation after the earthquake is started. The reference value is decided based on the sound collected by the microphone 4 in a prescribed period before starting the automatic recovering operation when the sound is in a prescribed level over the prescribed period, for instance.