The invention relates to a rotary drum machine and in particular relates to a cleaning chamber of a rotary drum machine. The cleaning chamber comprises a rotary drum arranged in a box body in a rotatable manner; driven carrying wheels for supporting the rotary drum are arranged on two sides of the lower part of the rotary drum in a padding manner; a guide wheel is arranged above the rotary drum; a first shaft is arranged at the center of the rotary drum; the front end of the first shaft extends out of the outer side of the box body; a square mounted bearing is fixed on the shaft diameter of the part, which extends out of the outer side of the box body, of the first shaft; a speed reducer is fixed on a bracket of the box body; the output end of the speed reducer is connected to the first shaft. The cleaning chamber disclosed by the invention is simple in structure; during working, the rotary drum only does autoroatation and turning motion without doing circumferential rotation, and a mechanical structure is eliminated; furthermore, driving and speed reduction mechanisms for the autoroatation are all arranged outside the chamber, so that the safety and the convenience in maintenance are achieved; a transmission shaft is protected by a labyrinth type seal, so that the service life is long; the material loading and unloading are facilitated and feasible.