PURPOSE: To execute the change and maintenance of a roll and chock quickly and surely.

CONSTITUTION: Roll change is executed by pulling the rolls 8 on which chocks 9 are mounted out of the main body 7 of mill of a tandem type cold rolling mill 1 onto a roll changing truck 10 and inserting rolls 8 which are stood by on a changing base 11 into the main body 7 of mill in a state where the chocks 9 are mounted. The rolls to be maintained are transferred from the changing truck 10 onto a transfer truck 14 and, after the transfer truck 14 is moved to a chock mounting and dismounting devices 17, the chocks are dismounted. The rolls 8 are delivered to an autoloader 20 by moving the transfer truck 14 to the connection position 18. At the time of maintaining the chocks 9, the chocks 9 are mounted on a dummy roll and taken out from the connection position 18 with a manual maintenace crane. The maintenance of the roll is executed in the roll maintaining area 5 where a cooling device 24, roll grinders 25 and roll racks 26 are arranged. The maintenance of the chocks is executed in the chock maintaining area 5 of a range where a gantry crane 22 travels.