An image reading apparatus includes a guide rod; a housing member having a guide part for abutting a document placed on a document table and positioning one side of the document on a table face of the document table and a first positioning part and a second positioning part projecting to the back side of the document table, when both end parts of the guide rod abut against the first positioning part and the second positioning part, the first positioning part and the second positioning part for positioning the guide rod at a position where the one side of the document positioned by the guide part and the longitudinal direction axis are parallel; a fix unit for pressing the guide rod against the first positioning part and the second positioning part; a carriage being fitted slidably into the guide rod; and a carriage drive section for moving the carriage along the guide rod.