An image forming apparatus comprising: a document transport unit configured to transport a document along a predetermined transport path; a first tray that is disposed adjacent to the document transport unit; a first document guide disposed above the first tray; and a second document guide disposed above the first tray, each of the first and second document guides including a plate that is disposed above the first tray with a gap therebetween; characterized by a second tray being located above the first tray, and being configured to be opened and closed, the second tray having a first surface facing downward when the second tray is closed, and facing upward when the second tray is in an open position in which the first surface of the second tray is configured to be used as a document placing surface, wherein, when the second tray is in the open position, the first surface of the second tray and a surface of the first tray are configured to be used as the feed tray, wherein, when the second tray is in the open position, the first surface of the second tray, a surface of the first document guide and a surface of the second document guide are configured to be used as the discharge tray, wherein, when the second tray is in the open position, an end portion of the second tray that is closest to the first tray is above the surface of the first tray and below the surface of the first document guide, wherein the document, that is transported, moves along the first surface of the second tray and then moves onto an upper surface of the first tray which is below the first surface of the second tray, wherein the document, that is discharged, moves along the upper surface of the plate of the first document guide and an upper surface of the plate of the second document guide, and then moves to the first surface of the second tray which is below the upper surface of the plate of the first document guide and an upper surface of the plate of the second document guide, and wherein the document, that is discharged, is discharged onto documents that have not been transported so as to overlap, the rear ends of the discharged documents remaining on the upper surface of the plate of the first document guide and the upper surface of the plate of the second document guide. a document transport unit configured to transport a document along a predetermined transport path; a first tray that is disposed adjacent to the document transport unit; a first document guide disposed above the first tray; and a second document guide disposed above the first tray, each of the first and second document guides including a plate that is disposed above the first tray with a gap therebetween; characterized by a second tray being located above the first tray, and being configured to be opened and closed, the second tray having a first surface facing downward when the second tray is closed, and facing upward when the second tray is in an open position in which the first surface of the second tray is configured to be used as a document placing surface, wherein, when the second tray is in the open position, the first surface of the second tray and a surface of the first tray are configured to be used as the feed tray, wherein, when the second tray is in the open position, the first surface of the second tray, a surface of the first document guide and a surface of the second document guide are configured to be used as the discharge tray, wherein, when the second tray is in the open position, an end portion of the second tray that is closest to the first tray is above the surface of the first tray and below the surface of the first document guide, wherein the document, that is transported, moves along the first surface of the second tray and then moves onto an upper surface of the first tray which is below the first surface of the second tray, wherein the document, that is discharged, moves along the upper surface of the plate of the first document guide and an upper surface of the plate of the second document guide, and then moves to the first surface of the second tray which is below the upper surface of the plate of the first document guide and an upper surface of the plate of the second document guide, and wherein the document, that is discharged, is discharged onto documents that have not been transported so as to overlap, the rear ends of the discharged documents remaining on the upper surface of the plate of the first document guide and the upper surface of the plate of the second document guide.