PURPOSE: To prevent high temperature heating due to a high speed of rotation of a barrel tank so as to improve polishing efficiency by providing ventilating holes in the barrel tank of small size.

CONSTITUTION: A turret disk 2 provides in its shaft 3 a gear 3' in a quantity two times or more the number of gears 4' provided in shafts 4 of barrel tanks 1, and a rotary speed in the barrel tank 1 is generated two times or more the rotary speed of the turret disk 2, fluidizing media in the barrel tank 1 to rotate at a high speed. Here, ventilating holes 5 are provided in a side part of the barrel tank 1. As a result, by releasing air, steam, etc. of high temperature to the outside from the ventilating holes 5 infiltrating cool air, polishing efficiency can be improved by decreasing a temperature in the barrel tank 1 prevented from its high temperature heating.