To provide an image reading apparatus 4 in which an image reading part 38 can be easily exchanged without attaching or detaching a mechanism deeply related to original transportation accuracy and image reading accuracy as represented by a reading roller 43.

The image reading apparatus 4 includes, inside a housing 3a: an exchangeable image reading portion 38; a document transportation path 30 curved so as to move around the image reading portion 38 in a side view; and a skew correction rollers 35, arranged on the document transportation path 30 at the transportation upstream side from the reading position 46 of the image reading portion 38. The image reading portion 38 passes through the document transportation path 30 at the transportation upstream side from the skew correction rollers 35, and is attached to and detached from the housing 3a.