Abstract: An optical system unit of a projector of the invention includes an illumination side block, an image producing block and a projection side block, the image producing block, in which a DMD display device is fixed which reflects rays of “off” state light to the outside of an entrance opening of a projection side optical system, has a resin accommodation case and a metallic light absorbing portion which is disposed on an inner surface of the accommodation case, an inner surface of the light absorbing portion has heat resisting properties and light absorbing properties, and the accommodation case has in an upper surface thereof a cooling opening for preventing the overheating of the resin which forms the accommodation case.