PURPOSE: To prevent an auxiliary reaper maintained at the target height from thrusting into a field and damaging due to great tilt of a machine body or sinking-in under conditions of unevenness in a field, an ill-drained paddy field, etc., in controlling the automatic horizontal posture.

CONSTITUTION: This combine harvester is obtained by installing a controlling means 100 for lifting and lowering of reaping capable of maintaining an auxiliary reaper provided on the rear side of a reaper at the target height based on information from height sending means 22 and 23 and a travel, lifting and lowering controlling means 101 capable of operating a lifting and lowering driving means 43 capable of respectively and separately performing operations to lift and lower left and right ground contact sites so as to maintain the left and right tilt angles of a mobile machine body at the set tilt angle in the lower limit reference mode for bringing the respective ground contact sites of the pair of the left and right mobile devices 1 close to the side of the mobile machine body based on the information from a left and right tilt angle sensing means 53. When a lowermost limit position sensing means 45 senses that both the respective ground contact sites are not the lowermost limit position of the machine body in the closest vicinity to the side of the mobile machine body, the target height of the auxiliary reaper is corrected to the side of lifting.