A polarizing split layer and a reflection layer are alternately provided on bonding surfaces between prism rods which constitute a polarized beam splitter array. Polarization conversion devices are bonded to emission surfaces of the prism rods from which linearly polarized light being reflected by the polarizing split layers and being reflected by the reflection layer are emitted. In the polarization conversion device, each edge line of a rectangular prism element is inclined by 45° with respect to a polarization direction of linearly polarized light being incident. On each inclined surface of the rectangular prism element, a retardation film whose optical axis matches the normal line of the inclined surface is formed. The retardation film serves as a uniaxial negative C plate which gives a phase difference of a ½ wavelength to incident light.