PURPOSE: To provide the title structure so designed that the operating state at an accumulating part for reaped crop and the on-off state of the sidewall of the accumulation part are mutually put to changeover using a specific reasonable mechanism, thereby reducing the working load on the workers and enabling the discharging work for the accumulated crop in its dumping to be automatically carried out in a state of reduced working load.

CONSTITUTION: The first changeover mechanism A is provided so as to be capable of changeover of an accumulating part 15 for reaped crop between (1) a lifting state in which said part 15 is actuated so as to be free to parallel ascend or descend against the travelling machine body 4 through the shrinkage or extension of a lifting link mechanism 19 and (2) a dumpling state in which said part 15 is put to rocking operation integrally with the lifting link mechanism 19 in a shrunk state around the linking support Y to the travelling machine body. Furthermore, the sidewall 32 of said part 15 is so constructed as to be free to open or close and along with this, the second changeover mechanism B (locking metal fixtures 38, diversionary metal fixtures 37, etc.), is provided so as to make a changeover to the attitude to discharge accumulated crop with the sidewall 32 in an opened state interlocking with the changeover to a dumping state for said part 15.