PURPOSE: To eliminate damage, etc., to a work during discharging contents.

CONSTITUTION: After polishing is completed, the opening/closing cover of a barrel polishing vessel 2 is replaced with a discharge bucket 6. The discharge bucket 6 is attached to the polishing vessel in a state where only one part of an opening part 5 of the polishing vessel 2 is opened, and extends along the outer peripheral surface of the barrel vessel 2 to form a bucket chamber 20, on the tip side of which a discharge opening 8 is opened, in the inside. Thus, as the barrel vessel 2 rotates, the contents (m) in the vessel flow from a part of opening of the opening part 5 into the bucket chamber 20 by small amounts. When the rotation is continued, the contents (m) in the bucket chamber 20 are advanced on the discharge opening 8 side, and discharged in sequence from the discharge opening 8 due to the rotation of the barrel vessel 2. As a result, damage, etc., to a work can be avoided. Further, when a guide chute 7 is arranged below and close to the barrel vessel 2 and along the rotational locus of the barrel vessel 2, the falling height of the contents (m) is reduced, and thus the falling impact can be reduced.