Provided is an exhaust nozzle and a method for changing an exhaust flowpath, whereby noise can be reduced by using a simple and light-weight mechanism without increasing the complexity and size of the structure of the exhaust nozzle, and furthermore, the efficiency during cruising at supersonic speeds can be improved. The rear end side of main nozzle pieces 110 of an exhaust nozzle 100 are provided swingably in an inward and outward direction of an exhaust flow path 101, about an open/close bend section 111 to the rear of an engine, coupling nozzle pieces 120 are coupled bendably to adjacent main nozzle pieces 110 on either side, and when the main nozzle pieces 110 are swung inside the exhaust flow path 101, the coupling nozzle pieces 120 form projecting sections 102 inside the exhaust flow path 101.