A projector that includes: an illumination device; an electro-optic modulator that modulates a luminous flux coming from the illumination device in accordance with image information; and a projection optical system that projects a light modulated by the electro-optic modulator. The illumination device is provided with: a light source device that emits a substantially parallel luminous flux to the side of a region to be illuminated; a first lens array including a plurality of first small lenses that divide the luminous flux coming from the light source device into a plurality of partial luminous fluxes; a second lens array including a plurality of second small lenses corresponding to the first small lenses of the first lens array; and a superimposing lens that superimposes, in the region to be illuminated, the partial luminous fluxes coming from the second small lenses of the second lens array. In the projector, each first small lens in the first lens array have a plane shape compressed in a direction which is either vertical or horizontal direction of the image formation region of the electro-optic modulator to make the luminous flux coming from the illumination device entirely illuminate an image formation region of the electro-optic modulator in the other direction thereof, and partially illuminate the image formation region in the one direction. The projector further includes: a light shielding member that is disposed between the illumination device and the electro-optic modulator to be substantially optically conjugate with the plurality of first small lenses and the electro-optic modulator for adjusting the cross section shape of the luminous flux; and a rotating prism that is disposed on the side of the electro-optic modulator of the light shielding member for scanning, on the image formation region of the electro-optic modulator, the luminous flux coming from the light shielding member along the one direction in synchronization with a frame rate of the electro-optic modulator. The light shielding member is provided with a stray light elimination member that reflects a reflection light from a light incident surface of the rotating prism in a direction different from the rotating prism.