A liquid crystal projection device includes a light source, a polymer dispersed liquid crystal panel for forming an optical image as a function of changes in the light scattering condition, a polarizing plate disposed on at lest one of the incident and exit sides of the liquid crystal panel with respect to the direction of travel of the light, and a projection lens for projecting the optical image onto a polarizing screen. The polarizing plate is removably and rotatably supported so that, by rotating the polarizing plate, the direction of the axis of polarization of the polarizing plate can be substantially aligned with the direction of the axis of the polarizing screen. The polarizing screen is utilized when the polarizing plate is mounted, but a non-polarizing screen may be utilized when the polarizing plate is not used, i.e., removed. Where the polarizing plates is used on both of the incident and exit sides of the panel, the direction of the axis of polarization of the polarizing plate on the incident side is to be substantially aligned with that of the polarizing plate on the exit side.