A program cartridge 4 is detachably attached to a body device 2. The game cartridge 4 stores a game program and certain data. The body device 2 reads the game program from the game cartridge 4 and executes the game program, and reads the certain data and refers to the data to display OBJ images and BG images provided with parallax in left and right display systems. That is to say, the body device 2 displays in the left and right display systems planar OBJ images having no parallax themselves shifted in the opposite directions in the right and left by the amount corresponding to provided parallax information. Also, the body device 2 cuts out left and right two BG images from a planar source image having no parallax by itself with the two images shifted in the opposite directions in the left and right by the provided parallax amount and displays the cut out left and right BG images at the same positions in the left and right display systems. Furthermore, the body device 2 displays planar BG images having no parallax themselves in the left and right display systems while shifting them by an amount corresponding to the provided parallax information in the left and right opposite directions. This way, an OBJ image and a BG image are displayed with parallax provided by a novel method.