An image rendering device holds a table which contains color and brightness values at positions specified by two-dimensional coordinates, where the color values are aligned so as to express a gradation of color tone along one coordinate axis of the two-dimensional coordinate, and the brightness values are aligned so as to express a gradation of brightness along the other coordinate axis. The image rendering device finds parameters corresponding to at least one of color and brightness of a polygon to be rendered, and generates an address for referencing a two-dimensional coordinate corresponding to each pixel composing the polygon based on the parameters. The image rendering device then acquires from the table color and/or brightness values corresponding to the address for referencing the two-dimensional coordinate. This successfully realizes natural expression by the image rendering device without preparing in advance a huge number of textures.