PURPOSE: To enable a car to perform communication with the other communication party destination car existing outside a communication area via another car.

CONSTITUTION: The present position data is acquired from the car of the other communication party destination outside a communication area. Under such conditions, a command for representing the present position data is sent to the car of the other party through a communication controller 9, a radio equipment 10 and an antenna 11 by relaying another car included in the communication area. Then the information indicating the present position data sent from the car of the other communication party destination in response to the command is received by the controller 9, the equipment 10 and the antenna 11 by relaying another car included in the communication area. Furthermore a main controller 4 is also provided to sends the present position data on a driver's own car to the car of the other communication party destination through the controller 9, the equipment 10 and the antenna 11 and via another car included in the communication are when a request is received from the car of the other communication party destination by relaying another car included in the communication area for the present position data on the driver's own car.