PURPOSE: To uniformize the brightness distribution of each color light beam and to reduce the color irregularity of a composite image by adjusting a brightness distribution difference due to an optical path length difference of each color light beam, etc., by using a correcting lens element which has a covex lens part and a concave lens part.

CONSTITUTION: The correcting lens 100 provided on the optical path of red light between reflecting mirrors 24 and 26 has the convex lens part 100A which increases the brightness by increasing the quantity of red light at the center part of an image and the concave lens part 100B which decreases the brightness by suppressing the quantity of red light at the peripheral part of the image. Then images of B, G, and R which are formed by liquid crystal light valves 18, 22, and 28 are put together by a dichroic prism 30 for color composition and the composite image is projected on a screen 34 by a projection lens 32. Consequently, the brightness distribution is approximated excellently at both the center and peripheral parts of the image and a color irregularity due to the irregularity of the brightness distribution on a screen 34 is reduced over the entire image.