To prevent a decrease in a packet transmission rate caused by a compressed radio band in transmitting a packet including vehicle information in an environment where roads are crossed and vehicle density is high.

A reception means 2 receives the packet for the vehicle information consisting of positional information, speed information, and time information transmitted from an other vehicle, and stores the vehicle information on a storage means 3. A range decision means 4 extracts the vehicle information after the past point of time by a predetermined time, on the vehicle present in a predetermined distance range from the self-vehicle out of the stored vehicle information, and in carrying out packet-transmission at a predetermined period the positional information, speed information, and time information on the self-vehicle, a transmission means 1 multiplexes the extracted information on the other vehicle to the packet and transmits the resultant packet.