In displaying map information, a map drawing unit generates map drawing data with an equal scale factor and a coordinate conversion unit does not execute coordinate conversion to an area a including the screen center and the lower area thereof, and writes in a VRAM the map drawing data that maintains the scale factor as it is. Further, the coordinate conversion unit writes in the VRAM map drawing data reduced with a specific reduction scale factor only in the horizontal direction as to each of the areas on the left and right of the area a; map drawing data reduced with a specific reduction scale factor only in the vertical direction as to the area directly above the area a; and map drawing data reduced with specific reduction scale factors both in the horizontal and vertical directions as to each of the areas located obliquely left above and obliquely right above the area a. Thus, the navigation system of the invention lightens the burden of calculation processing, displays detailed information of the most important area surrounding the vehicle position, and provides a seemingly bird's-eye view display, namely, quasi-three-dimensional map information, that gives a user an extensive view.