PURPOSE: To prevent biting shock and large variation in tension and to preform smooth biting rolling even in a one roll driving system by setting an opening between a pair of rolls immediately before biting the stock.

CONSTITUTION: A rolled stock 1 is rolled between a couple of two rolls of a driven roll 15 and a non-driven roll 18. Before the stock 1 is bitten by the rolls 15, 18, the roll 18 is strongly presses onto the roll 15 by use of a drafting device and is rotated at a speed higher than a prescribed rolling speed. For that, a speed down amount of the roll 18 is previously found and a speed down amount corresponding to a time necessary to set a roll opening based on the previously found speed down amount is found and the rotating speed at kissing both rolls 15, 18 before biting the stock 1 is increased by the above corresponded speed down amount. At biting the stock 1, a speed of the roll 18 is decreased to about a prescribed speed, so that smooth biting for the stock 1 is performable.