PURPOSE: To easily add vector information by extracting map data and additional information image data which are additionally described from a map data base and an additional information data base, and displaying those data while overlapping the map data base and the additional information data base.

CONSTITUTION: An output device 7 outputs a map 8 from a map data base 1 and the data of an additional information data base 2, and an image input device 9 inputs the image of the map data including the additional information which is additionally described. An extraction circuit 10 extracts the inputted image of the map data and the image data of the additional information additionally described from the map data base 1 and the additional information data base 2, and a vectorizing circuit 11 converts the image data of the extracted additional information to an image vector and registers it on the additional information data base 2. Afterwards, a display circuit 3 generates a display data from the data in the map data base 1 and the additional information data base 2 and displays it on a display device 5. Thus, the additional information can be easily inputted.