1. A map building apparatus comprising: a landmark map generating unit which generates a landmark map which includes location information and respective local images of each of a plurality of landmarks; a pattern extracting unit which extracts a pattern formed by landmarks, of the plurality of landmarks, identified as being of a same kind by use of the location information and the local images; and a landmark map adjusting unit which adjusts the landmark map by use of the extracted pattern formed by the landmarks of the identified same kind.