PURPOSE: To obtain a sufficient attraction force at the attraction time of a work and a smooth rotation at a polishing time, by equipping a seal member for opening and closing the upper part of an air leading passage in the air leading passage formed in the space between a fixed part and rotating part.

CONSTITUTION: In the case of a work 9 being held with its vacuum attraction 14 from an air introduction port 3, the air of an air introduction passage 12 is pulled upward, and an outside air pressure 15 is flowed into a space 16 via an air introduction passage 13, so the air introduction passage 12 is closed with a seal member 11 being moved upward, and the vacuum attraction 14 acts only on the attraction of the work 9 via an air introduction passage 8. At the polishing time of the work 9 by a polishing tool 17, the seal member 11 is pushed down with the air flowed into the air introduction passage 12 with an air exhaust 18 being performed to the air introduction port 3, so the contact of a fixed part 1 and rotating part 7 is released, and the friction resistance force to a rotation force is not generated. Thus, the rotational slide in the polishing of a work is almost eliminated excepting those by the bearing which holds a rotation part and a smooth rotation can be realized.