PURPOSE: To provide effect of sufficient work hardening by eccentrifying the position where a working roller is pressed against a cylinder surface relative to the direction where the load is directed to the axial center.

CONSTITUTION: A working roller 6 is pressed against the cylinder surface of a work by bringing a first holder 1 and a second holder 2 close to each other under the prescribed load while the work is rotated around the axial center O. An angle 8 is formed between the direction S where the force F is directed to the axial center O of the work and the direction T where the load is directed from the pressed position to the axial center O by the eccentricity Δ, and the load F is decomposed into the force f1 (Fcosθ) directed to the axial center O by this angle θ, and the force f2 (Fcosθ) in the tangential direction orthogonal to the force f1 directed to the axial center O. The force f1 directed to the axial center O causes the strain in the radial direction of the work, while the force f2 in the tangential direction which is securely generated causes the plastic deformation of the cylinder surface by the sliding motion.