To enable a desired part of a map to be seen well when an enlarged image of a crossing is displayed.

When the size and position for displaying the enlarged image of a crossing are designated by the operation section 4, the size and position are registered in a display position/display size storage section 8. When a crossing to pass CPi recorded in a scheduled travel route storage section 7 is the next crossing to be enlarged and displayed, the plotting section 12, based on a map data including the present position, plots a map image in a prescribed scale with the north in upward direction, together with a present position mark in a first area 11a of image memory section 11, and, based on the shape data of the crossing CPi in the map data, plots an enlarged picture of the crossing CPi in the size, specified by a user on a position corresponding to the position specified by the user in the second area 11b. A compositing section 13, when a vehicle approaches the crossing CPi within a prescribed distance and an enlarge display mode of the crossing CPi is turned on, superposes the enlarged image of the crossing of the second area 11b on the map image of the first area 11a, and coverts it into image signals to be outputted into a display section 3 and is displayed on a screen.