Vehicle management system, vehicle-mounted device, vehicle management method, and program

A vehicle-mounted device is configured to identify another vehicle from an image generated by photographing the surroundings of a host vehicle using a photographing device. The vehicle-mounted device is configured to detect identification information of the another vehicle on the basis of a signal received via inter-vehicle communication with a vehicle-mounted device of the another vehicle located in a communication range of the inter-vehicle communication. The vehicle-mounted device is configured to determine whether the identification information corresponding to the another vehicle identified from an image has been acquired.