PROBLEM TO BE SOLVED: To provide a combine harvester, detecting the moisture content of grains without crushing the grains accommodated in a grain tank.SOLUTION: A moisture content detecting unit includes: a cover fixed to the inner surface of a peripheral wall of a grain tank a storing part having a fixed quantity case disposed in the cover a capacitance type sensor for detecting the moisture content of grains stored in the fixed quantity case and an electric actuator for changing the state of the storing part according to the control of a controller. The storing part selectively takes a receiving state of receiving and storing grains in the fixed quantity case, a fixed quantity holding state of refusing receipt of new grains while storing the grains in the fixed quantity case, and a discharge state of discharging the grains in the fixed quantity case according to the operation of the electric actuator.
