To efficiently perform the repair and inspection work of a roll surface by oneself.

A chock 5 is mounted on a roll 3 and a support member 19 is attached to the chock 5 with an electromagnet 23 freely attachably and detachably. A motor 18 is fixed on the support member 19 and a 1st gear 28 is fixed on the output shaft 24 of the motor 18. A 2nd gear 29 and a positioning member 21 are mounted on the joint part 11 of the roll 3 and the 1st gear 28 and the 2nd gear 29 are engaged. When the motor 18 is driven, the roll 3 is rotationally driven through the 1st and 2nd gears 28, 29, and then, worker performs the repair and inspection work of the roll surface efficiently by himself.