PURPOSE: To solve the problem about thermal expansion of a lining, prolong the cycle time of re-lining, and simplify the repair works.

CONSTITUTION: At the peripheral edge of the oversurface of a rotary trough 13, a detaining groove 23 is provided over the circumference with the opening facing the oversurface in the rotational axis direction, and therein a plurality of segments 21a made of shape memory alloy are loosely fitted at a constant spacing with possibility of removing. When the temp. rises due to polishing process, the lining 19 of this rotary trough 13 is going to expand outward in the radial direction of the trough 13 so as to push and bend the segments 21a outward in the radial direction. Even though the segments 21a have curved as out of limit for resisting this power, returning to the stored shape takes place when a further rise of temp. causes exceeding the transfer point, so that the lining 19 is intruded inward in the radial direction and hindered from expansion to the outside.