A general purpose combined harvester and thresher comprising a first rotor (51) and a second rotor (52) provided in a thresh unit (5) and arranged longitudinally in parallel to each other with axes thereof right and left, and a first receiving net (55) and a second receiving net (56) arranged below the respective rotors to define a first treating chamber (D1) and second treating chamber (D2). A grain tank (79) is arranged above the threst unit (5), a base end of a discharge auger (83) is arranged outside the grain tank (79), an engine (84) is arranged behind the grain tank (79), and a transmission casing (85) is arranged below the engines A tooth bar (T1) is provided on an outer peripheral surface of the first rotor (51) facing a grain rod inlet (36), and a screw vane (53) has a pitch (P) equal to a width of a rear end of a feeder housing (35). A terminal end of a return conveyor (81) for returning of a second product communicates with the first treating chamber (D1).