This combine harvester is provided with: an engine control unit 141 for controlling the speed of an engine 18 a horizontal orientation control unit 421 that controls an orientation varying mechanism 200 for varying the orientation of a body frame 10 through the operation of an actuator that uses motive power from the engine 18 the horizontal orientation control unit 421 bringing the body frame 10 to a horizontal orientation a yield measurement unit 144 for measuring the yield of grain stored in a grain tank 5 on the basis of the measurement result of a load cell 60 for measuring the weight of the grain tank 5 an activation operation tool 9a for outputting an activation signal which causes the yield measurement unit 144 to activate yield measurement and a yield control unit 153 for sending the engine control unit 141 a high speed rotation command to drive the engine 18 at the rated speed in response to the activation signal and sending the horizontal orientation control unit 421 a horizontal orientation command to bring the body frame 10 to a horizontal orientation.
