PROBLEM TO BE SOLVED: To provide a combine-harvester for retaining an arrangement space for a urea water tank without enlarging the external dimensions of a combine-harvester.SOLUTION: A combine-harvester comprises: an engine as a power source mounted on a running airframe 1; an exhaust gas purification case for removing a nitrogen oxide substance from the inside of the exhaust gas of the engine; a urea water tank 174 for accommodating urea water fed to the exhaust gas purification case; and a grain tank 7 for accommodating harvested grain. The grain tank 7 is formed with a cavity 254 arranged with the urea water tank 174.SELECTED DRAWING: Figure 15