A combine harvester includes a conveyance mechanism for conveying grains obtained by a thresher for threshing grain culms reaped from a field to a grain tank, a measurer (340) for measuring the amount of grain conveyed to the grain tank as a conveyed yield, a yield assignment calculator (631) for calculating a minimal section yield, which is a yield per minimal section, by assigning the conveyed yield to a minimal section in the field, a grain conveyance state detector (632) for detecting a grain conveyance state of the conveyance mechanism (7), a yield corrector (633) for correcting the minimal section yield in accordance with the grain conveyance state, and a yield distribution data generator (661) for generating yield distribution data that represents a yield distribution in the field, based on the minimal section yield.
