PURPOSE: To constitute a second treating cylinder having a relatively large diameter, to increase threshing, treating and selecting effects and to compact a threshing and treating device by making a second treating chamber of net material along approximately the whole circumference of the second treating cylinder.

CONSTITUTION: Grain culms fed to a threshing chamber are threshed and treated by a threshing cylinder 2. Treated materials such as straw waste, untreated grains, etc., produced in the threshing chamber 3 are sent from an exhaust port first treating chamber 7, threshed and treated while being sent backward by a first treating cylinder 8 and from the cylinder to a second treating chamber 11. In the second treating cylinder, the grain culms are threshed and treated while being sent backward by a second treating cylinder 12. Grains threshed and treated in each treating chamber are leaked downward from a treating net to a lower selecting chamber and treated materials of dust such as straw waste are discharged from a dust discharging hole 14 to the outside.