PURPOSE: To eliminate the deformation at the rear end of a material and to improve the yield and dimensional accuracy of a finish pipe by changing the number of revolution of the roll in the prescribed stand which is preselected on the down stream side of pass stands to exert concentrically tension to the material.

CONSTITUTION: The command for decreasing the number of revolution of the rolls is emitted to each stand upon lapse of the prescribed second after the passage of a blank material through the 1st stand and the rate of decreasing the number of revolution of the rolls with respect to the reference number of revolution of the rolls of the 3rdW6th stands is controlled at the point of the time when the blank pipe passes through the 2nd stand. The forward and backward tension is exerted to the material which is bitten in the 5th and 6th stands as the stand for finishing the wall thickness, by which the increase in rolling load is suppressed and the generation of the deformation at the rear end is suppressed.