An illuminator includes: a first light source and a second light source that are disposed substantially symmetrically with respect to an illumination optical axis, wherein each of the first and second light sources includes an arc tube, a first reflector disposed to surround part of the entire space around the optical axis of the arc tube, the first reflector reflecting the light emitted from the arc tube toward an object to be illuminated, and a second reflector disposed on the opposite side of the optical axis of the arc tube to the first reflector, the second reflector reflecting the light emitted from the arc tube toward the first reflector.