1. A stereoscopic image display device, comprising: a display panel in which pixels each constituted with N×N pieces (N is a natural number of 2 or larger) of sub-pixels colored in M (M is a natural number of 1 or larger) primary colors are arranged in matrix; and an optical separation module in which optical elements which distribute exit light from each of the pixels according to parallax images in a first direction and a second direction along layout of the pixels are arranged by being corresponded to each of the pixels, wherein: the sub-pixels neighboring to each other within each of the pixels are of different colors from each other; array pitches of the sub-pixels are uniform in the first and second directions; same numbers of the parallax images are displayed for each of the first direction and the second direction within each of the pixels; and numbers of the sub-pixels in different colors within the parallax images are equivalent.