A paper sheet bundling apparatus configured to bundle stacked paper sheets with a tape, the paper sheet bundling apparatus comprising: a stacking unit configured to stack paper sheets; a tape loop forming unit configured to form a small tape loop from the tape and configured to feed the tape to enlarge the small tape loop into a large tape loop, the tape loop forming unit which includes a tape gripping part configured to rotate while gripping the tape at an end portion thereof to form the small tape loop and a feeder which is configured to feed the tape to enlarge the small tape loop into the large tape loop and configured to form the large tape loop under the tape gripping part; a paper sheet transport unit configured to grip the stacked paper sheets stacked in the stacking unit to transport the stacked paper sheets into the large tape loop; and a guide configured to come into contact with an outer peripheral surface of the large tape loop to define the shape of the large tape loop when the tape loop forming unit forms the large tape loop, characterized in that the guide includes a lower guide which is configured to come into contact with the outer peripheral surface of the large tape loop from a side under the large tape loop to define the shape of the large tape loop, and a lateral guide which is configured to come into contact with the outer peripheral surface of the large tape loop horizontally with respect to the large tape loop to define the shape of the large tape loop, wherein the lower guide is provided with a displacement mechanism which is configured to move the lower guide in the vertical direction. a stacking unit configured to stack paper sheets; a tape loop forming unit configured to form a small tape loop from the tape and configured to feed the tape to enlarge the small tape loop into a large tape loop, the tape loop forming unit which includes a tape gripping part configured to rotate while gripping the tape at an end portion thereof to form the small tape loop and a feeder which is configured to feed the tape to enlarge the small tape loop into the large tape loop and configured to form the large tape loop under the tape gripping part; a paper sheet transport unit configured to grip the stacked paper sheets stacked in the stacking unit to transport the stacked paper sheets into the large tape loop; and a guide configured to come into contact with an outer peripheral surface of the large tape loop to define the shape of the large tape loop when the tape loop forming unit forms the large tape loop, characterized in that the guide includes a lower guide which is configured to come into contact with the outer peripheral surface of the large tape loop from a side under the large tape loop to define the shape of the large tape loop, and a lateral guide which is configured to come into contact with the outer peripheral surface of the large tape loop horizontally with respect to the large tape loop to define the shape of the large tape loop, a lower guide which is configured to come into contact with the outer peripheral surface of the large tape loop from a side under the large tape loop to define the shape of the large tape loop, and a lateral guide which is configured to come into contact with the outer peripheral surface of the large tape loop horizontally with respect to the large tape loop to define the shape of the large tape loop, wherein the lower guide is provided with a displacement mechanism which is configured to move the lower guide in the vertical direction.