To accurately and speedily find a passenger who does not return after getting out of a vehicle, if any.

A passenger card 1 stores identification information on a passenger and sends the identification information with a radio signal. A controller 4 detects the identification information by a card reader 2 and when the passenger bearing the passenger card gets out of the vehicle, the identification information detected from the card is stored in a getting-out passenger memory and passengers who get out of the vehicle are counted. When a passenger who carries a passenger card 1 gets on the vehicle, the identification information detected from the card is erased from the identification information stored in the getting-out passenger memory and the number of the getting-out passengers is decreased, one by one. The controller 4 displays the identification information, stored in the getting-out passenger memory, on a display board 5.