An on-vehicle device sends an allocation request for a wireless resource to a roadside device. The roadside device, in response to receiving this allocation request, allocates a roadside-vehicle resource that is a wireless resource for roadside-vehicle communication with the on-vehicle device, and an inter-vehicle resource that is a wireless resource for inter-vehicle communication between on-vehicle devices; and sends the allocation information to the on-vehicle device. The on-vehicle device carries out roadside-vehicle communication with the roadside device using the roadside-vehicle resource identified with the allocation information received from the roadside device, and carries out inter-vehicle communication with other on-vehicle devices using the inter-vehicle resource identified with the allocation information. Thereby, roadside-vehicle communication and inter-vehicle communication can be achieved with higher utilization of wireless resources while avoiding the hidden terminal problem.