Color separation and color synthesis optical system and reflection type projection display apparatus

Disclosed is a color separation and color synthesis optical system provided between a light source portion and a projection optical system in a reflection type projection display apparatus, which color-separates a white color beam emitted from the light source portion into three primary color light beams of R (red), G (green) and B (blue), guides the three primary color light beams to a plurality of spatial light modulators corresponding to R, G and B, and color-synthesizes color light beams optically modulated by the respective spatial light modulators for the colors depending on video signals to emit a color-synthesized light beam, wherein at least one or more wavelength-selective polarization converting plates which rotate a plane of polarization of a specific color light beam by 90 degrees are located, and the wavelength-selective polarization converting plate is adhered to an incidence plane and/or an emission plane of a polarization beam splitter by adhesive with a slight gap.