A tray which holds documents to be fed has a document holding portion which holds document in a stacked state thereon and guide members which are arranged on the document holding portion in the cross direction (document width direction) and at least one of which is movable in the document width direction. The document feeding tray further has an extending portion which extends from the document holding portion in the feeding direction (document length direction) to freely increase or decrease the extending amount and a adjusting mechanism which decreases the extending amount of the extending portion as a distance between the guide members becomes narrower and increases the extending portion as the distance between the guide members becomes wider.