The present invention is able to cause an enlarged map displayed as a sub-screen in a wide-region map screen to move in any given manner at a high speed. A navigation device is provided with: a map display means that displays a wide-region map screen indicating a wide-region map, and displays an enlarged map screen indicating a partial enlarged map resulting from having enlarged a region that is a portion of the wide-region map, displaying the enlarged map screen superimposed on the wide-region map screen at the display position of the region that is a portion; a speed calculation means that calculates a speed pertaining to the motion of the enlarged map screen; an enlarged map generation means that, on the basis of vector data of a detailed map resulting from enlarging the wide-region map, generates the enlarged map resulting from enlarging a predetermined region containing the region that is a portion of the wide-region map; and a selection means that, when the speed pertaining to motion is at least a baseline speed, selects the region that is a portion of the wide-region map as the partial enlarged map, and when the speed pertaining to motion is less than the baseline speed, selects a region corresponding to the region that is a portion in the enlarged map as the partial enlarged map.