PURPOSE: To display a first external image signal on a liquid crystal display element, and further to display an external image signal inputted from the outside excepting the first external image signal on the liquid crystal display element. Further, to branch a luminous flux outgoing from a light source to plural optical paths at every liquid crystal display element displaying respective image signals and to project the luminous fluxes on these optical paths on a screen.

CONSTITUTION: The liquid crystal display elements 7R, 7G, 7B displaying the first external image signal (color image) beforehand color resolved and the liquid crystal display element 80 displaying a second external image signal are provided, and further, R/G/B optical paths and an N optical path respectively transmitting through these liquid crystal display elements are provided. The luminous fluxes outgoing from a common light source are branched to respective optical paths, and are transmitted through respective liquid crystal display elements. The luminous fluxes passing through the R/G/B optical paths among the transmission optical fluxes are color synthesized to be incident on a projection lens. By the projection lens, the luminous fluxes color synthesized on the R/G /B optical paths and the optical flux on the N optical path are projected to respective areas at every external image signal on the screen.