Included are an identification data input unit (11) to which identification data for identifying an occupant of a vehicle is input, a preference data storage unit (12) configured to store preference data regarding a preference of the occupant in association with the identification data, an object acquisition unit (13) configured to acquire object data of objects existing around an occupant on board the vehicle, a determination unit (15) configured to determine whether or not an object included in the object data is visually or audibly recognizable by the occupant on board the vehicle, and a notification data generator (16) configured to generate notification data for the occupant on board the vehicle based on the preference data of the occupant and the object for which the determination unit determines that it is recognizable by the occupant. The preference data of the occupant is stored in the preference data storage unit and associated with the identification data.