A stereoscopic display device of an embodiment includes a display device having pixels developing either one color of red, green and blue. A vertical period of pixel rows comprising the pixels arranged in one row in a lateral direction is three times a lateral period of the pixels, the pixels developing red, green and blue are alternately arranged in a lateral direction in the same row, the pixels in one row of two rows adjacent in a vertical direction are arranged such that lateral positions thereof are shifted to the pixels in the other row by ½ of the lateral period of the pixels, the pixels in rows adjacent in the same column through one row interposed therebetween are the pixels developing different colors of red, green and blue, and an average value of pitches of the elemental images is larger than a width of pieces of the pixels.