In the combine provided with the side cover portion covering the power transmission device provided on the side of the threshing device from the side of the gas, the dust entering the gap between the threshing device and the side cover portion falls from the gap, and bounces over the crawler traveling device. The right ITO makes it difficult to enter the gap between the threshing device and the side cover. A lower cover portion 60 is provided to cover the gap between the lower end portion of the side cover portion 50 and the lower end portion 8f of the threshing device 8. Among the lower cover portions 60, a plurality of inclined members 68 are provided in portions 63 positioned above the rear end side portion of the crawler traveling device 2. The plurality of inclined members 68 are provided in an inclined state when viewed from the side of the aircraft, and a space S is provided in the front-rear direction of the aircraft, from the gap between the side cover portion 50 and the threshing apparatus 8. In addition to allowing the dust to fall downward, the crawler travel device 2 picks up the spring soil. Further, a combine can be configured to quickly and reliably perform the transition of the clutch mechanism that controls the feed chain to the on state. A clutch operation unit A is provided that transmits the driving force of the motor 1034 through the operation wire W so that the clutch mechanism FC is turned on by the normal rotation of the motor 1034 and turned off by the reverse rotation. The clutch operation unit A comprises a cam body 1035 that rotates with the driving force of the motor 1034, and a cam follower 1039 that operates the operation wire W by following and displacing the cam surface 1035a of the cam body 1035. It is done. A restraining portion R is provided as an increase/deceleration mechanism that speeds up the displacement speed of the cam follower 1039 when the motor 1034 reversely rotates while the clutch mechanism FC is in the off state. I
