PURPOSE: To suppress the wear of guide shoes and to prevent the formation of flaws on the surface of a pipe stock for a seamless steel pipe to be formed by supplying a liquid lubricating agent to the specific part between a round billet and the guide shoes in the stage of forming the seamless steel pipe from the round billet by a Mannesmann system.

CONSTITUTION: The seamless steel pipe is formed by piercing the heated round billet with double circular conical type cross helical rolls 1, 2 and a plug 5 attached to a mandrel 11. The upper guide shoe 3 and the lower guide shoe 4 are supported in the upper and lower part of the rolling pass line by an upper oblique lifting and supporting device 6 and a lower oblique lifting an supporting device 7. both shoes 6, 8 are made liftable in the diagonal direction along the rolls on the advance side of the rotation of the pipe stock with regard to the respective guide shoes. At the same time, the liquid lubricating oil 13 is pressurized by a pump 15 and is sprayed by branch pipes 21, 2 under the specified pressure to the entire region of the shoulder part of the guide shoes on the advance side of the rotation of the round billet where the max. load is exerted to the shoes, then prevent the formation of flows.