Provided is a navigation system capable of, when an emergency situation occurs, immediately distributing, to a mobile terminal that is a client terminal located in a region impacted by the emergency situation, required information according to the terminal position in order of priority. During an emergency situation such as when a disaster or the like occurs, information on the emergency situation is distributed from a server, as a priority, simultaneously to each mobile terminal located in an area that is strongly impacted (for example, areas marked with a circled 1) immediately, regardless of when terminal position information is received from the mobile terminals, and the information on the emergency situation is displayed on a display device of the mobile terminal and a display device of a DA device to which same was distributed.