An optical apparatus including a light combining optical apparatus that combines color light fluxes modulated by a first and a second light modulators with each other includes an inorganic polarizer disposed on the light exiting side of the first light modulator, a transparent substrate that is in contact with the inorganic polarizer and transmits light, a supporting section that supports the first light modulator and is attached to the light combining optical apparatus, and a clamping section that clamps, along with the supporting section, the inorganic polarizer and the transparent substrate. The clamping section includes a engaging section that engages with the supporting section and an urging section that urges the inorganic polarizer toward the transparent substrate when the engaging section engages with the supporting section, and the supporting section has a receiving section that receives the transparent substrate pressed by the urging section.