An image display device comprises a first control part, a first storage, and a display part. The first storage holds rendering elements, each of which includes a combination of rendering target information and rendering setting information, and a priority order assigned to each rendering element. The rendering target information includes data identification information which designates three-dimensional data of a rendering target and mask information which designates a rendering target area. The rendering setting information includes information which designates a two-dimensional image rendering method and rendering parameter. The first control part determines, based on the rendering setting information and the mask information, whether executing priority processing is necessary. If it is determined that it is necessary to execute the priority processing, either the mask information or the rendering parameter is modified, and a two-dimensional image is rendered based on the rendering elements whereupon the priority processing is executed.
