PURPOSE: To reduce the shoe reaction of a roller shoe and to improve its quality and yield by equipping linear grooves nearly in parallel and at an equal interval to the advancing direction of rolling of a material to be rolled and on the surface corresponding to a rolling part of a pair of rolling rolls arranged obliquely.

CONSTITUTION: Each roll of a pair of rolling rolls is arranged obliquely at a fixed lead angle linear unidirectional grooves 35 inclining to a roll shaft 31 at an angle β are knurled on the rolled part 33 of the surface in the peripheral direction of the rolling roll 30 in a prescribed pitch P and at an equal interval. A grip part 32 of the rolling roll 30 is knurled crosswise. Roller shoes are arranged on both sides of a rolled area enclosed by both rolling rolls. A rolled tube stock is elongated further by the frictional force of the grooves 35 in the advancing direction and restrained from expanding in the peripheral direction. Consequently, since the reaction arising in the roller shoe can be limited, a long life of the roller shoe can be kept and the quantity and yield of the product can be improved, through the strength of the roller shoe is low.