To solve problems of an intermediate area harvesting work to perform reaping work by driving a combine harvester into a middle part of unreaped culm rows while shifting a right-end grass-dividing rod outward to set a reaping width to be extended outward rather than a right end of a crawler, which comprise liability of falling and tilting of unreaped culm divided by the right-end grass-dividing rod toward the reaped ground side after passing the grass-dividing rod, and scattering of cut straws to an adjacent ground and unreaped culm when the scattering width of a discharged culm cutter is unchanged even by shifting the right-end grass-dividing rod outward.

There is provided a reaped culm processing apparatus characterized by coupled switching operability of a side cover 9 in such a manner that the side cover 9 at a right-end of the discharged culm cutter 7 is shifted toward the outside of a cut straw scattering width by shifting the right-end grass-dividing rod 5 of the reaping apparatus 6 to inner side of the reaping width with a switching lever 8 operable from a driver's seat 3, and the side cover 9 is shifted inward by shifting the grass-dividing rod 5 outward.