PROBLEM TO BE SOLVED: To provide a combine harvester enabled to install an exhaust gas purification device compactly.SOLUTION: A combine harvester of the present invention comprises: a reaper 3; a thresher 5; an engine 14 for driving the reaper 3 or the thresher 5; an exhaust gas purification device 74 for removing a nitrogen oxide substance from the exhaust gas of the engine 14; an engine room 97 for mounting the engine 14 therein; and a grain tank 7 for carrying-in the grain cropped. The exhaust gas purification device 74 is disposed at the back of the engine room 97, and a urea water supply device 175 for supplying the urea water to the exhaust gas purification device 74 is disposed on the lower side of the exhaust gas purification device 74.SELECTED DRAWING: Figure 3