1. A three-dimensional map display system comprising: a display terminal that displays a three-dimensional map; a memory that stores a map database including map data for displaying the three-dimensional map, the map data including multiple levels of map data each having a different level of map details; and a display controller that refers to the map database and generates the three-dimensional map viewed from a specified viewpoint position and in a specified gaze direction, thereby allowing the display terminal to display the three-dimensional map thereon, wherein the display controller sequentially draws a plurality of view areas starting from a distant view area toward a close view area concurrently using a plurality of different levels of map data in accordance with a distance of each view area from the viewpoint position, such that the view area more distant from the viewpoint position is drawn with the map data of a rougher level having a lower level of map details, while the view area closer to the viewpoint position is drawn with the map data of a finer level having a higher level of map details, wherein the map data includes at least: first data of the rougher level for the distant view area having first depth information; and second data of the finer level for a closer view area adjacent to the distant view area, the second data having second depth information, the first data and the second data overlapping each other across a border between the distant view area and the closer view area, whereby an overlapping area including the border is concurrently represented by the first data and the second data having respective depth information, and wherein the display controller draws the overlapping area by overwriting the closer view area on the distant view area in the three-dimensional map regardless of the depth information of each point in the distant view area such that a ground surface in the overlapping area is displayed based on the second data.