Since a light emitting surface in a cross section perpendicular to the longitudinal direction of a light guide is formed to have a smaller width than a reflecting surface, light of an LED, which is incident from an end surface of the light guide and is scattered throughout the entirety of the longitudinal direction in the reflecting surface, is condensed toward the light emitting surface, and is then emitted in the form of a band toward a document from the light emitting surface. Therefore, it is possible to provide a CIS module including an illumination unit having a new configuration capable of illuminating a portion where the document and an optical axis of the lens array included in the lens unit intersect, in the form of a band with high efficiency using the illumination unit.