To display the rendering image of a three-dimensional model with high quality while reducing a processing load.

A computer 20 attaches, to a three-dimensional model, each bit position in case of expressing coordinates (x, y) as a binary digit, a monochrome vertically striped pattern for x coordinates corresponding to a bit value and an inversion pattern obtained by inverting this, and a monochrome horizontally striped pattern for y coordinates and an inversion pattern obtained by inverting this for performing rendering, and compares the vertically striped pattern with the inversion pattern, and compares the horizontally striped pattern with the inversion pattern, in the rendered image, and discriminates the black and white of each coordinate (x, y) of the vertically striped pattern and the horizontally striped pattern, and sets correspondence between coordinates (x, y) of the rendered image and coordinates (Xt(x, y), Yt(x, y)) of the texture. A viewer 40 performs image plotting in the coordinates (x, y) of the display image based on the gradation values of the coordinates (Xt(x, y), Yt(x, y)) of the texture according to preliminarily set image plotting information.