PURPOSE: To save the labor of a changing job by installing the cantilever mandrel on which a sleeve is fitted outside to slide freely, the gripping arm for fitting leveling rolls on the mandrel and inserting leveling rolls into the principal shaft and the changing device body.

CONSTITUTION: Leveling rolls 1 are assembled in a roller leveler B. A roll change device A is moved to a sleeved leveling rolls 1 placed on a roll table, and the shaft center of the mandrel 3 and leveling rolls 1 are coincided. A slide chop 16 is moved to the nose of the mandrel 13 by stretching an air cylinder 19 for shifting, and the arm 18a is thrown down by stretching an air cylinder 17 for hooking and an arm pin 10 is inserted in a hook hole. The leveling rolls 1 are fitted on the mandrel 3 by shortening the cylinder 19 for shifting. Then the roll change device A is moved to the main shaft 2 of roll, and the recess of holding plates 21 and the projection of the mandrel 3 are inserted and engaged. By stretching the cylinder 19, the leveling rolls 1 are moved to the principal shaft 2 of the roll. The arm for hooking is released and the roll change device A is moved to an off-line place.