PURPOSE: To reliably convey sheets by providing a mechanism releasing the conveyance force after conveying sheets to the following conveying means in reverse conveyance.

CONSTITUTION: A sheet fed to a reverse section 19 is direction downward along a guide 71 and bitten by flange rollers 65, 67 and a press roller 73. In this case, a sensor 61 is turned on. When the sheet tip is bent by a guide 53 and bitten by rollers 77, 81, a sensor 203 is turned on, then the roller 73 is separated from rollers 65, 67, and the sheet conveyance force is released. The sheet is fed by rollers 77, 81 and sent to a switch back section 21, then when the sheet rear end goes out of the sensor 61, the sensor 61 is turned off, and the roller 77 is reverse-rotated after a preset time. The sheet is reverse-fed along a guide 53 and bitten by rollers 87, 93, then a sensor 83 is turned on, and the conveyance force of rollers 81, 87 is released. The sheet is further stored on a sheet discharge tray 23 by rollers 87, 93.