1. A 3D map display system for displaying a 3D map on which a ground surface and a feature are represented three-dimensionally, comprising: a map database for storing map data representing a 3D shape of the ground surface and the feature; a first drawing unit for drawing the ground surface and the feature by executing depth determination by referring to the map database; and a second drawing unit for drawing a target feature, which is a feature in which at least a part thereof is hidden by a ground surface or other features in the drawing by the first drawing unit, by overwriting the target feature on a drawing result by the first drawing unit by using the map data without executing depth determination with respect to the drawing result by the first drawing unit.