Traffic information is provided to an in-vehicle unit of a vehicle located in a shadow portion of a large-sized vehicle and to an in-vehicle unit of a vehicle at a location separated from an intersection 193. A UHF beacon unit 112 is installed at the intersection 193, thereby distributing the traffic information using a UHF beacon signal having a diffraction characteristic. This arrangement can allow the in-vehicle unit of the vehicle located in the shadow portion of the large-sized vehicle as well to receive the traffic information. Further, since the UHF signal propagates far, this arrangement can allow the in-vehicle unit of the vehicle at the location separated from the intersection 193 as well to receive the traffic information. The UHF beacon unit 112 transmits, to a plurality of concentric zones, UHF beacon signals with different traffic information set therein for the different zones, by time division. At this time, the UHF beacon unit 112 transmits the UHF beacon signals with the different traffic information set therein, with different transmission output powers.