PURPOSE: To efficiently process a workpiece without scattering abrasive by arranging several magnetic so as to alternatively change the polarities of magnetic poles which are arranged adjacent to each other along the outer surface of a rotary table, and by retaining magnetic abrasive on the outer surface of the rotary table with the use of a magnetic force.

CONSTITUTION: Several magnets 5 are arranged so as to alternately change the polarities of magnetic poles which are arranged adjacent to each other along the outer surface of a rotary table 2. Next, then magnetic abrasive M is retained on the outer surface of the rotary table 2 by a magnetic force so as to process a workpiece W. With this arrangement in which the magnetic abrasive M is retained on the outer surface of the rotary table 2 by the magnetic force, the magnetic abrasive M magnetically attracted to the outer surface of the rotary table is prevented from scattering, even though the rotary table 2 is rotated, and accordingly the density of the abrasive can be maintained to be constant. Thus, the magnetic abrasive M retained on the rotary table 2 makes contact with the workpiece W, thereby it is possible to efficiently polish the workpiece W.