PURPOSE: To enhance productivity by sucking a part of medium out of a tank, dressing part of the medium, and thereby circulating it back to a fixed tank thereafter when the all surfaces of each work is polished while the mixture of the works and medium is centrifugally flowed with a rotary disk rotated within the fixed tank.

CONSTITUTION: The specified number of works and the specified amount of medium are put in a fixed tank 5, and when a rotary disk 6 is rotated by a drive means 7, the mass composed of the works and the like is flowed and stirred while being spirally moved, so that the entire surface of each work is polished. In this case, an exhauster 13 is drive, a part of medium is sucked out of the mass by means of suction air flow generated within a transport pipe 9 through a screen 11 so as to be introduced in a separation means 10. Chips and other dust are removed so as to be discharged out of a discharge pipe 12, and meanwhile medium is moved to the vibration shift 18 of a surface treatment means 16 by way of a discharge section 15. Medium is dressed by projected material blasted out of a projection means 22 during movement over a shift section 21, and it is circulated to the inside of the fixed tank 5 by way of a circulating port 31 thereafter.