1. A stereoscopic image data structure for a stereoscopic display device that displays a stereoscopic image, with parallaxes being given in a horizontal direction but not given in a vertical direction, the stereoscopic display device comprising: a display unit that has a display face on which a parallax interleaved image for stereoscopic display is displayed, with pixels being arranged with a first horizontal pitch in the horizontal direction; and a parallax barrier that has linear optical apertures disposed to face the display face and arranged with a second horizontal pitch in the horizontal direction, the optical apertures inclined from the vertical direction, the second horizontal pitch being equal to an integral multiple (n) of the first horizontal pitch, the parallax barrier directing light rays emitted from pixels at horizontal intervals of n pixels as parallel light rays toward the viewing zone, the stereoscopic image data structure comprising: a parallax component image data representing n or more parallax component images, each having accumulated pixels that cause the pixels to generate the parallel light rays in the same parallax direction in the viewing zone, and having different numbers of horizontal pixels, wherein n combined images with the same numbers of vertical and horizontal pixels are a unit to be converted into a parallax interleaved image, the n combined images being formed by combining one or more parallax component images with parallax directions different from each other by n.