User labor relating to determining on an alignment condition is reduced and a stable conveying operation is realized by aligning a sheet bundle also when a sheet bundle is added. A sheet bundle composed of multiple sheet materials is placed on a loading platform. An encoder pulse unit detects the amount of the sheet bundle placed on the loading platform based on the opening amount of a pressure plate. A control unit determines on an alignment condition according to the amount of the sheet bundle. Rotating members align the sheet bundle in accordance with the alignment condition. When it is determined that another sheet bundle has been added to the loading platform, the control unit updates the alignment condition according to the total amount of the other sheet bundle and the sheet bundle remaining on the loading platform.