An image reading apparatus for reading an image on a document surface, the image reading apparatus comprising:
- a document-supporting unit that supports the document and transmits light;
- a light source that, from a direction inclined with respect to a line perpendicular to the document surface, irradiates the document surface with an irradiation beam transmitted through the document-supporting unit;
- and
- an image reading unit that reads the image in accordance with light reflected from the document surface and thereby generates image data;
- wherein
- the document-supporting unit enables varying degree that the irradiation beam scatters in passing through the document-supporting unit.