An image reading apparatus comprising: a main unit including: a processing portion; and a guide portion; an openable unit connected to the main unit such that the openable unit pivots around a rotation axis and moves up and down relative to the main unit, the openable unit including: a document tray on which a document is placed; a feeder configured to feed a document placed on the document tray along a feed path; and a reading portion disposed facing the feed path and configured to read an image of the document passing through the feed path; and a flexible flat cable configured to electrically connect the reading portion of the openable unit and the processing portion of the main unit, wherein the processing portion is configured to perform processes relating to image data of the document based on an output signal of at least the reading portion, wherein the guide portion is configured to guide the flexible flat cable such that the flexible flat cable follows pivotal or vertical movement of the openable unit, and wherein the guide portion includes a rib configured to fix a predetermined portion of the flexible flat cable and to hold the flexible flat cable to have a generally U-shaped slack portion between the predetermined portion of the flexible flat cable fixed at the rib and the openable unit when viewed from a direction of the rotation axis of the openable unit, characterized in that the rib has an upper end which is bent downward, the flexible flat cable hangs down from the openable unit into the main unit, extends generally vertically upward, changes its course downward along a shape of the upper end, and extends further downward generally vertically, the guide portion further includes a lid portion, and the upper end is vertically spaced apart from the lid portion. a main unit including: a processing portion; and a guide portion; a processing portion; and a guide portion; an openable unit connected to the main unit such that the openable unit pivots around a rotation axis and moves up and down relative to the main unit, the openable unit including: a document tray on which a document is placed; a feeder configured to feed a document placed on the document tray along a feed path; and a reading portion disposed facing the feed path and configured to read an image of the document passing through the feed path; and a document tray on which a document is placed; a feeder configured to feed a document placed on the document tray along a feed path; and a reading portion disposed facing the feed path and configured to read an image of the document passing through the feed path; and a flexible flat cable configured to electrically connect the reading portion of the openable unit and the processing portion of the main unit, wherein the processing portion is configured to perform processes relating to image data of the document based on an output signal of at least the reading portion, wherein the guide portion is configured to guide the flexible flat cable such that the flexible flat cable follows pivotal or vertical movement of the openable unit, and wherein the guide portion includes a rib configured to fix a predetermined portion of the flexible flat cable and to hold the flexible flat cable to have a generally U-shaped slack portion between the predetermined portion of the flexible flat cable fixed at the rib and the openable unit when viewed from a direction of the rotation axis of the openable unit, characterized in that the rib has an upper end which is bent downward, the flexible flat cable hangs down from the openable unit into the main unit, extends generally vertically upward, changes its course downward along a shape of the upper end, and extends further downward generally vertically, the guide portion further includes a lid portion, and the upper end is vertically spaced apart from the lid portion.