A projector including an illumination device, an electra-optic modulator and a projection optical system. The illumination device is provided with a light source 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; a second lens array including a plurality of second small lenses corresponding to the first lens array; and a superimposing lens that superimposes the partial luminous fluxes coming from the second lens array. The projector further including a light shielding member provided with a stray light elimination member disposed 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 for scanning the luminous flux from the light shelding member in synchronization with a frame rate of the electro-optic modulator.