An address retrieval system includes: an address database having a tree structure in which regional names, which constitute an address, and which indicate the areas of each scale ranging from the large area down to the small area, are associated with nodes, wherein a child node has a regional name indicating an area that is larger than the area indicated by the regional name owned by its parent node; an input portion that inputs the regional names; a central processor that searches the address database for the child node having the regional name inputted by the input portion as its parent node; and an output portion that outputs the regional name corresponding to the child node retrieved by the central processor.