Map display device and method for controlling indication of map

A storage medium stores map data divided into unit areas. A control circuit indicates a map on an image display unit according to the map data. The map data includes name records, which respectively correspond to names to be indicated in the map. Each of the name records includes information specifying a character string of corresponding one of the names and information specifying an indication range of the character string in the map. An updating unit updates a part of the unit areas of the map data. An extracting unit extracts a pair of the same character strings, which are overlapped and indicated in the map or closely indicated in the map, with reference to the name records, after update of the part of the unit areas of the map data. A prohibiting unit prohibits indication of one of the extracted pair in the map.