A polarizing device including a plurality of polarized light radiating units for radiating polarized light rays each of which is polarized in a particular direction, a rotary reflector for receiving light rays emitted by the plurality of polarized light radiating units while being rotated and for outputting reflected light in a certain direction, and an analyzer disposed midway an optical path of the reflected light from the rotary reflector to set a polarization direction of the reflected light in a certain direction, wherein each of the polarized light radiating units includes a light source, a polarizer for setting a polarization direction of light from the light source, and a first compensator for compensating for a change in a state of polarization attributable to the rotary reflector, and the plurality of polarized light radiating units are disposed in a radial arrangement that is centered at the rotary reflector.