PURPOSE: To remove perfectly a residual strain by loading a fluid pressure larger than the surface pressure in shrink fitting from both sides of a shrink fitting part at the same time, and floating a sleeve through the whole shrink fitting part.

CONSTITUTION: An annular fluid pressure chamber 4 is formed at the central part of a variable crown roll 1 between an arbor 2 and a sleeve 3 fitted to the body of arbor 2. A pressurized oil is introduced from the outside to the chamber 4 through a rotary joint 5 and an introducing port 6. In the roll 1 constituted in this way, annular auxiliary chambers 7 are provided to the shrink fitting part at both ends of the sleeve 3. When the pressurized oil having a pressure higher than the surface pressure in shrink fitting is supplied to the chambers 7, the sleeve 3 is floated through the whole zone of shrink fitting, and an ununiformed residual strain caused by the shrink fitting is removed.