A three-dimensional image/two-dimensional image display device includes a plurality of display pixels, and a lenticular lens for three-dimensional display. Each display pixel is consisted of M×N number of sub-pixels to be viewed from N view points. A pitch a of sub-pixels arranged in the longitudinal direction of ridge projection of the lenticular lens and a pitch b of the sub-pixels arranged in a direction orthogonal to the longitudinal direction of the lenticular lens satisfy the following expression. The M×N number of sub-pixels included in each of said display pixels are formed within a square area. a:b=N:1