PURPOSE: To eliminate the need of the alignment of a picture element without reducing an image element and to project a color image by making a color filter circulate and move in the optical path of the transmitted light of a monochromatic liquid crystal image.

CONSTITUTION: A filter plate 21 is rotated so that the R filter 21r thereof is inserted in the optical path L when the picture display signal of R color is outputted to a liquid crystal panel 7, the G filter 21g is inserted with respect to the picture display signal of G color and the B filter 21b is inserted with respect to the picture display signal of B color. Therefore, monochromatic image light transmitted through the panel 7 is colored by the corresponding color filter and changed to color image light. Thus, the monochromatic liquid crystal image is projected as the color image by simple constitution without reducing the image element and without executing the alignment of the picture element on a screen.