A bundle of rays is incident in a lens array and converted into sub-bundles of rays. The sub-bundles of rays are separated by a color separator into first and second sub-bundles of rays of different colors. The first and the second sub-bundles of rays are combined by other lens arrays into a first and a second bundle of rays of uniform illuminance, respectively. The first and second bundle of rays of uniform illuminance are applied polarization beam splitting and then polarization angle conversion by polarization converters, to be converted into first and second linearly polarized beams, respectively. The second linearly polarized beams are separated by a color separator, provided on an optical path of the second linearly polarized beams, into third and fourth linearly polarized beams of different colors. The first, third and fourth linearly polarized beams are modulated by liquid crystal display devices, provided on optical paths of the first, third and fourth linearly polarized beams, respectively, with input video signals into first, second and third modulated beams. The first, second and third modulated beams are combined by a color combiner into a combined bundle of rays to be projected for displaying images carried by the video signals.