A polarizing beam splitter apparatus of a light valve image projection system includes a polarizing beam splitter commonly usable as a polarizer and an analyzer, and a quarter wave plate in combination. In the polarizing beam splitter apparatus, a quarter wave plate is arranged in a light path along which a light passes out from and passes back again to the polarizing beam splitter in such a manner that either a fast axis or a slow axis of the quarter wave plate is perpendicular to a plane containing both a first optical axis and a second optical axis of the polarizing beam splitter, so that the angular range of a light to be used can be increased. In the light valve image projection system, a light outputted from a light source is incident through a polarizing beam splitter apparatus to a light valve, and an effective component of the light reflected from the light valve is projected through the polarizing beam splitter apparatus and a projection lens on a projection screen. The polarizing beam splitter apparatus is high in polarization efficiency even if the range of incident angle of a light to be used is large, so that a projected image highly improved in contrast and brightness can be obtained.