PURPOSE: To obtain a combine harvester excellent in threshing performance with hardly any fear of causing the residual threshing even in the case of a large amount of materials to be threshed in a combine harvester for sensing an engine load and controlling a speed changer for travel so as to maintain the engine load within the target load range.

CONSTITUTION: The objective combine harvester is obtained by installing a changing means for changing the rotational frequency of a threshing drum provided in a threshing chamber and controlling the changing means so as to provide a higher rotational frequency (R) of the threshing drum than the routine one (R0) by a prescribed extent (ΔR) when the speed changer for travel is controlled so as to decrease the car speed.