An image exposure system is formed by a spatial light modulator element comprising a number of two-dimensionally arranged pixel portions each modulating light projected thereon, a light source which projects light onto the spatial light modulator element and an imaging optical system which includes a micro lens array and forms on a photosensitive material an image of light modulated by the spatial light modulator element, the micro lens array being made up of micro lenses which are arranged like an array and collect light from the pixel portions of the spatial light modulator element. Each micro lens of the micro lens array has an aspherical surface or a refractive index profile which corrects aberration due to distortion of the pixel portions or has a shape of lens aperture which does not permit light from a periphery of each of the pixel portions of the spatial light modulator element.