1. A stereoscopic image display device, comprising: a display panel in which pixels each constituted with N×N pieces of sub-pixels colored in M primary colors are arranged in a first direction and in a second direction transverse to the first direction, as a matrix; and an optical separation module in which optical elements which distribute exit light from each of the pixels according to parallax images to a plurality equal to N of viewpoints in each of the first direction and the second direction along a layout of the pixels that is arranged to correspond to each of the pixels in a one-to-one correspondence, wherein: N is a natural number of 2 or larger; M is a natural number of 1 or larger; sub-pixels neighboring 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; numbers of the sub-pixels in different colors within the parallax images are equivalent; each neighboring pixel has a different sub-pixel color layout; and sub-pixels of the pixels neighboring to each other at a boundary of each of the pixels are of different colors from each other.