We introduce an instrument that is used to change the rolling-mill rolls and disk shoes of
steel pipe rolling mills. This instrument includes mechanisms that is used to raise and lower a top and bottom cradle, which hold a roll of a rolling mill and a carriage disposed below the bottom cradle and movable transversely. By this way, the cradles are moved in and out of the rolling mill housing transversely by the carriage, and a plurality of holding devices each rotatable about a fixed shaft are selectively positioned opposite to a pair of chocks, which hold a pair of disk shoes for movement in parallel motion to change the disk shoes.