PURPOSE: To improve yield and productivity by rolling a looped sheet material down to a prescribed sheet thickness while circulating said material in a rolling equipment train and setting and changing a roll gap, inlet side tension and outlet side tension at every pass.

CONSTITUTION: The sheet material S is let off from a reel 7. The let off sheet material is cut when the front end thereof arrives at a shearing machine 9 by passing the shearing machine 9, a welding machine 11, bridle rolls 13, 3, 5, a looper 15, and a rolling mill 1. The cut part thereof constitutes the rear end part of the sheet material S. The front end part of the sheet material S and said rear end part are welded by the welding machine 11 to form the loop of the sheet material S. Rolling is started after formation of the loop and is continuously executed from one lass to prescribed passes. The rolling speed is lowered at every change of the passes and the setting of the roll gap, the inlet side tension nd outlet side tension is changed. The material S is sheared by the shearing machine 9 when the rolling progresses to the prescribed sheet thickness. The sheared material is taken up on a reel 7.