COMBINE

A combine including: a grain tank that stores grains sorted by a sort unit that swings to sort grains fallen from a threshing cylinder unit; a yield measuring device 50 that measures the amount of grain put in the grain tank; a unit yield calculation unit 81 that calculates a unit yield per unit plot in a cultivated field, using the amount of grain; an opening degree adjustment unit 1 that adjusts the opening degree of a chaff sheave of the sort unit in accordance with a threshing state of the threshing apparatus; a mode setting unit 73 that sets a yield accuracy priority mode in which priority is given to accuracy of the unit yield calculation performed by the unit yield calculation unit 81; and a yield accuracy maintenance unit 74 that in response to the mode setting unit 73 setting the yield accuracy priority mode, forcibly fixes the opening degree of the chaff sheave at a specific opening degree.