A surrounding information obtaining unit determines whether a first vehicle has traveled on a different road than a road on which a host vehicle travels, on the basis of information indicating roads and a facility present around the host vehicle and a travel state of the first vehicle. A difference checking unit checks whether a target road determined to have been traveled by the first vehicle is included in host vehicle map information. A wireless communication unit inquires whether an unknown target road confirmed not to be included in the host vehicle map information is included in master map information in a server device. When the unknown target road is included in the master map information, the wireless communication unit receives updating map information including the unknown target road from the server device. A map updating unit updates the host vehicle map information using the updating map information.