1. An autonomous mobile system for a mobile body which moves while localizing itself in a space, the system comprising: measuring means for measuring whether objects are present or absent in each of regions determined by dividing the space into a plurality of segments according to a predetermined rule; storage means into which map data is stored that indicates a region of the determined regions that has been set as having a stationary object in the region; means for determining, from frequency of the object detection by the measuring means during a predetermined time for each of the determined regions, whether the object that has been detected in the region is a stationary object or a moving object; and means for localizing the mobile body by matching the region having therein the stationary object which the determining means has determined to be present, and the region that was set in the map data as having a stationary object in the region.