Abstract: A color image reading apparatus includes a light receiving device having a plurality of line sensors disposed on a surface of a common substrate, an imaging optical system for forming an image of an object, a blazed diffraction grating, disposed in an optical path between the imaging optical system and the light receiving device, for color-separating a beam from the object into a plurality of color beams, a first optical element provided near a position where the plurality of color beams are focused in a sub scanning cross section by the imaging optical system and a second optical element provided in an optical path between the first optical element and the light receiving device. The plurality of color beams color-separated by the blazed diffraction grating are focused on the light receiving device through the first optical element and the second optical element.