To provide a rotary plastic working method raising the working accuracy.

A rolling mill 1 which is formed as a horizontal wedge roll or a horizontal wedge rolling mill includes a first work roll 2 which is rotatable or rotated around an axial line A of rotation and a second work roll 3 which is rotatable or rotated around an axial line B of rotation. Because the axial lines A and B of rotation are arranged in parallel to each other and up and down in a view in the direction of gravity, the work rolls 2 and 3 are also arranged up and down each other. The work roll has a generally cylindrical outer surface. The interval between the cylindrical outer surfaces of both work rolls 2 and 3 is shown by W. A permanent magnet motor especially a torque motor is provided as a driving motor 4 for driving two work rolls 2, 3. Furthermore, the rotational position of the work roll is detected with a position detector and the rotational speed of the work roll is controlled in accordance with the rotational position.