Threshing device

The invention provides a threshing unit for improving treatment performance of threshing processing objects in a secondary processing barrel and a dust exhaust processing barrel. The secondary objects cannot be threshed in the processing barrel are processed in a secondary processing chamber of the secondary processing barrel with a helicoid supprted by an axis, dust exhaust objects of the processing chamber are processed in a dust exhaust processing chamber with a helicoid supprted by an axis. Because the helicoid is collocated continuously in the transporting direction of processed objects and is a continuous helicoid, comparing with embeded teeth arranged brokenly, the helicoid can improve the transporting efficiency of processed objects. Moreover, through setting the dust exhaust processing barrel helicoid diameter of the communication port which is between the processing chamber and the dust exhaust processing chamber be larger than that of the helicoid at the rear side thereof, the setback processed abi