The map-display-area determining unit determines an area in which a map is to be displayed. The road-information obtaining unit obtains, from map data transmitted from a map-data distributing server, curved-point coordinate information and name information of a traffic route. A map-display-data generating unit determines a display position for each of a character or symbol included in a character/symbol string in the name information so that the character or symbol is positioned along the traffic route without interfering with another character or symbol, and generates map display data for displaying the character or symbol at the determined display position.