PURPOSE: To prevent deformations and breakdowns of gear teeth, gear shafts, and spindles, etc., by generation of a strong loop torque in a power transmission system by intermediately installing a shear pin in the power transmission system between a gear of a gear-tie type rolling mill and a rolling roll.

CONSTITUTION: A couple of gears 4, 4 meshing each other and driven by a motor 2 are actuated and a couple of upper and lower work rolls 1, 1 are rotated through spindles 3, 3 connected to respective gear shafts of the gears 4, 4 to perform rolling. As for a gear-tie type rolling mill having such a structure, a coupling 5 with a shear pin is intermediately installed on the spindle 3 as a power transmission system between the above gears 4, 4 and the work rolls 1, 1. The shear pin of the coupling 5 is broken by a shear force when a storing loop generated in the system in the case that a sheet stock is broken and the stock winds around the work roll 1 and in other cases in the said rolling mill. Thus, deformations of gear teeth and breakdowns of the spindles 3 and gear shafts are prevented.