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 having 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 light control unit disposed to face the display face, the light control unit having optical apertures 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 n times (n being an integer number) the first horizontal pitch, the light control unit controlling directions of light rays emitted from the display unit, 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 parallel light rays in a respective parallax direction in a viewing zone, and each having a different number of horizontal pixels, wherein the parallax interleaved image is formed by combining n combined images, each combined image having a same number of vertical pixels as the number of horizontal pixels, wherein each combined image is formed by combining one or more parallax component images with parallax directions different from each other by n.