1. A map building apparatus comprising: a landmark map generating unit, comprising at least one processing device, to generate a landmark map which includes location information and respective local images of each of a plurality of landmarks; a pattern extracting unit to extract a pattern formed by grouping 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 to adjust the landmark map in accordance with a comparison between obstacle information and the extracted pattern formed by grouping the landmarks of the identified same kind by repositioning at least one landmark based on the comparison.