Retrieving an on-map position is executed within a targeted search area that is one of search areas. Search information items are stored for retrieving. Each of the search information items is related to one of the search areas. Area-designating information items are also stored for designating one of the search areas. When a user selects, as a search item, one of address-book information items, address information included in the selected address-book information item is collated with the area-designating information items. A corresponding search area is thereby automatically designated as the updated targeted search area. Thus, based on the address-book information and area-designating information, the targeted search area is automatically switched into a search area that includes the retrieved on-map position. User's procedure in retrieving the on-map position can be thereby reduced.