To provide a combine harvester solving problems on fluctuation of belt tension caused by fluctuation of center distance between an output shaft and an input shaft by vibration of the engine.

The combine harvester comprises traveling equipment 2 on the downward and a thresher 3 on the upward, and a reaping device 4 on the front side of the machine frame 1, an engine 10 on the machine frame 1 intervening a mount rubber 13, stretching a belt 20 between an output pulley 17 installed on the output shaft 16 of the engine 10 and an input pulley 24 of a hydraulic continuously variable transmission 22 installed on a transmission case 21 of the traveling equipment 2, and setting a tension pulley 25 installed on the top end of a tension arm 26 to contact to the belt 20, wherein the tension arm 26 is set to be energized by a tension spring 28 locked on a fitting member 11 of the mount rubber 13 to a tension side.