An optical processing unit comprises a dichroic filter to filtrate a green-colored light off a white light, a polarizer to selects a certain linearly polarized light component from the filtrated green-color light and a dichroic mirror to resolve the light into two lights as the first light beam and the second light beam divided at a predetermined wave length, two beam splitters to change the propagation direction of the light beams, liquid crystal devices to reflect the light beams thereon, reflective image superimposing devices to superimpose image information in the reflection onto two image lights and a dichroic mirror to compose these two image lights into an identically single image light which directs toward a direction in a single optical axis. This invention can provide an optical process unit that realizes a high fidelity stereo image display system wherein the pixel-shifted image generation and the stereo image display are compatible.