An image reading apparatus, including: a light source; a reflection member changing a traveling direction of the light reflected from an original; an optical system imaging the light; a photoelectric converter receiving the light from the optical system to convert the light into an electric signal; and a light passing and blocking member disposed between the optical system and the photoelectric converter, and provided with an aperture through which the light from the optical system imaged on the photoelectric converter passes, the blocking member blocking non-convergent light which is not imaged on the photoelectric converter, wherein the blocking member has an inclined surface surrounding the aperture so that the aperture gets smaller from the optical system toward the photoelectric converter, and a hypothetical extension plane extending from the inclined surface toward the photoelectric converter intersects with an optical axis of the optical system without intersecting with photoelectric converter.