For example, if multiple pieces of information arrive at and/or are generated in a vehicle at the same time, MMS optimizes selection of information to be communicated, selection of information communicating means, selection of information communication style and selection of various parameters such as communication timing, according to priority order given integrally to the multiple pieces of information, so as to communicate the multiple pieces of information to a vehicle driver effectively. Further, it communicates information effectively using appropriate resources corresponding to a parameter selected by this optimization.