An original-document illumination apparatus includes an illuminated face on which an original-document is placed. The original-document illumination apparatus also includes a light-source unit having a plurality of light-emitting elements which are arranged along the main-scanning direction of the original-document and which illuminate the original-document. The light source unit is movable in a sub-scanning direction that is orthogonal to the main-scanning direction. In addition, the original-document illumination apparatus includes a lens array disposed between the illuminated face and the light-source unit, and having a plurality of convergent lenses. A luminous flux from each of the light-emitting elements of the light-source unit is radiated onto the illuminated face through each of the lenses of the lens array.