A combine harvester, comprising: a threshing device configured to perform a threshing process of threshing a crop, a grain tank configured to store grain obtained by the threshing process, a grain discharging device configured to discharge grain to be stored in the grain tank to the outside of a vehicle body, a travel driving device configured to drive travel of the vehicle body, and an engine that serves as a power source, wherein there is provided a first relay shaft to which power is transmitted from an output shaft of the engine, and the power of the engine is transmitted from the first relay shaft to the grain discharging device and the travel driving device in a branched manner, wherein the output shaft is provided at a location on one side of the engine in the vehicle body left-right direction, power is transmitted from the output shaft to a plurality of driven devices provided in the threshing device, Z and the first relay shaft extends from a location on one side in the vehicle body left-right direction to a location on the other side, characterized in that the first relay shaft is configured such that power from the output shaft is input to one side in the vehicle body left-right direction, and power is output from the other side in the vehicle body left-right direction to the grain discharging device and the travel driving device, and in that a power transmission unit for the plurality of driven devices is provided on one side in the vehicle body left-right direction with respect to the engine, and a power transmission unit for the grain discharging device and the travel driving device are provided on the other side in the vehicle body left-right direction with respect to the engine. a threshing device configured to perform a threshing process of threshing a crop, a grain tank configured to store grain obtained by the threshing process, a grain discharging device configured to discharge grain to be stored in the grain tank to the outside of a vehicle body, a travel driving device configured to drive travel of the vehicle body, and an engine that serves as a power source, wherein there is provided a first relay shaft to which power is transmitted from an output shaft of the engine, and the power of the engine is transmitted from the first relay shaft to the grain discharging device and the travel driving device in a branched manner, wherein the output shaft is provided at a location on one side of the engine in the vehicle body left-right direction, power is transmitted from the output shaft to a plurality of driven devices provided in the threshing device, Z and the first relay shaft extends from a location on one side in the vehicle body left-right direction to a location on the other side, characterized in that the first relay shaft is configured such that power from the output shaft is input to one side in the vehicle body left-right direction, and power is output from the other side in the vehicle body left-right direction to the grain discharging device and the travel driving device, and in that a power transmission unit for the plurality of driven devices is provided on one side in the vehicle body left-right direction with respect to the engine, and a power transmission unit for the grain discharging device and the travel driving device are provided on the other side in the vehicle body left-right direction with respect to the engine.