A transmission determination unit determines whether or not transmission of common information is impossible, by using a throughput that is required when the common information is transmitted, a throughput that is estimated from a communication state with a vehicular server, and a processing load of an in-vehicle information device. A transmission unit transmits vehicle-side information to the vehicular server at a set transmission timing, and, when the above transmission is determined to be impossible by the transmission determination unit, transmits a transmission impossible message to the vehicular server.