A sheet processing system A includes a sheet processing apparatus 1 that transports and stores a sheet in one of short-edge leading orientation and long-edge leading orientation; a sheet housing section 3 that stores the sheet in the other of the short-edge leading orientation and the long-edge leading orientation; and an orientation changing section 4 that transports the sheet between the sheet processing apparatus 1 and the sheet housing section 3, changes transport orientation of the sheets which is being transported between the short-edge leading orientation and the long-edge leading orientation.