To provide a grain-conveying device of a combine harvester with a pneumatic conveying method capable of smoothly performing the discharge of cereal grains from a grain tank to a cereal-discharging auger.

This combine equipped with the grain tank for temporarily storing the cereal grains after threshing reaped cereal culms and the auger, is provided by installing a plurality of cereal grain-discharging ports for discharging the cereal grains to the auger at the bottom part of the grain tank. In this case, by installing a shutter at each of the cereal grain-discharging ports at the bottom part of the grain tank, it is possible to adjust the cereal grain- discharging amount easily. The cereal grain-discharging amount is not decreased as compared with a case of using a spiral conveyer (a screw conveyer), and also by increasing the number of the cereal grain-discharging ports, it is possible to increase the cereal grain-discharging amount relatively. Also, in spite of installing the plurality of grain-discharging ports, it is possible to gather the discharged cereal grains by one discharging pipe, and the constitution of the conveying system is simple.