PURPOSE: To stabilize the performance of this liquid crystal display and to reduce its production cost by arranging the 1st polarizing plate on the light source side from a light decomposing system and arranging the 2nd polarizing plate on the projecting optical system side from a light synthesizing system.

CONSTITUTION: When polarizing plates 27a, 27b are respectively arranged on the prestage and post stage of a process for driving light from a light source 2 into three color beams R, G, B without arranging the polarizing plates 27a, 27b in respective optical paths obtained by dividing light from the light source 2 into three color beams R, G, B, operation can be fully attained only by one pair of polarizing plates 27a, 27b to be used in an equivalent state to a convensional method. Since a purpose for maximizing the contrast ratio of liquid crystal elements 6a to 6c can be attained by once of the adjusting work of the polarizing plates 27a, 27b, the production cost of the liquid crystal projector can be suppressed while stabilizing the performance of the projector.