A light source apparatus includes a light emitting element configured to emit light having a first wavelength band, a polarization separation element configured to separate the light having the first wavelength band into a first linear polarization light and a second linear polarization light having polarization directions different from each other, a wavelength conversion element configured to convert the first linear polarization light into a third linear polarization light having a wavelength band different from the first wavelength band, and a combination element configured to combine the second linear polarization light and the third linear polarization light with each other. Light from the light source apparatus maintains a polarization state and illuminates a light modulation element via an illumination optical system.