PURPOSE: To eliminate affection by heat when bodies to be polished are polished by flowing abrasives in a variable magnetic field.

CONSTITUTION: A container storing cylinder 4 is provided in a closed box 1, and a container in which abrasives and bodies to be polished are filled is placed on the container storing cylinder 4. A rotating plate 5 is provided under the container storing cylinder 4, a magnet 7 is installed on the rotating plate 5, variable magnetic field is generated in the container by the rotation of the rotating plate 5, and the abrasives are made to flow, for polishing the bodies to be polished. In this case, fins 13 are installed on the rotating plate 5, air flow is generated in the box 1 by the rotation of the fins 13, and heat generated during polishing is transferred to the box 1 through air flow, to radiate heat from the box 1 to the outside.