A sheet transport device includes a transport path along which a sheet is transported in one direction, the sheet being transported with a corner at a leading end of the sheet being located on a first lateral side of the path, a sheet rotating section that rotates the sheet so as to increase an angle of the sheet and so as to orient the leading end, a sheet moving section that moves the sheet toward the first lateral side, and plural sheet butting portions that are arranged side-by-side in the one direction, on the first lateral side, the sheet butting portions allowing the moved sheet to be butted thereagainst to orient the sheet in the one direction. When the sheet is butted against the sheet butting portions to be oriented in the one direction, the corner is located at a position where no sheet butting portions are provided.