PURPOSE: To enable the polishing where cracks or chips are extremely few, especially for a fragile material easy to cause cracks or chips such as ceramics by putting the motion of media in liquid-form medium in spiral shape by making one side of unbalance weights heavier than the other.

CONSTITUTION: Vibration is caused by attaching unbalance weights 2a and 2b to both ends of a vibration motor 3, and it is given to a circle-shaped barrel vessel 1 so as to perform barrel-polishing. At this time, the quantity of liquid- form medium to be put in the barrel vessel 1 is made the one by which a work and media are all under the level of water, and one side 2b of the unbalance weights 2a and 2b at both ends of the vibration motor 3 is adjusted to be heavier than the other 2b so as to put the motion of the media in liquid-form medium in spiral shape at time of vibration.