To provide a color switching means, an optical switching element and a color image display device possible to obtain high efficient illumination, reduced in color smear at a dynamic picture reproducing time, high in hourly light availability and necessary of only one image display element.

A beam outgoing from a white light source 101 arrives at a dichronic mirror 103. A reflected beam is switched by the optical switching element 101, and is optical path synthesized with other optical paths by the dichroic mirror 105. The optical switching element 104 is turned ON only for the time width of nearly 1/3 of one period by a synchronous control circuit 107. Other optical paths are constituted similarly also. The image display element 115 is illuminated by color beams of RGB switched in time division to be projected by a projection lens 116.