PROBLEM TO BE SOLVED: To ensure reliability of an electric motor operation in a grain culm conveyance device composed of a feed chain and a rail.SOLUTION: A combine includes: a grain culm conveyance device CU whose state can be changed between a first state and a second state an electric motor unit MU including electric motors 81, 119 shifting the grain culm conveyance device CU from the first state to second state by means of rotation exceeding a predetermined rotation angle from a home position a minute rotation command part 231 outputting a minute rotation command minutely rotating the electric motor unit MU at the predetermined angle or less rotation detectors 83, 119A detecting the rotation of the electric motors and an abnormality determination part 240 determining abnormality occurrence when the minute rotation of the electric motors is not detected by the rotation detectors 83, 119A in spite of the output of the minute rotation command.SELECTED DRAWING: Figure 1
