PURPOSE: To stabilize piercing operation by controlling the speed of a driving rolling roll so that the outside diameter of biting part of material in piercing rolling with press roll is less than the target value.

CONSTITUTION: In piercing with press roll that a stock 4-1 to be pierced is inserted between the driving rolling rolls 1 which are provided in the facing direction by adding a force in the axial direction and pierced by entering a plug 5 into the axial center part, the outside diameter of the biting part of material in piercing rolling is measured with a photoelectric biting width meter 7 and piercing is executed by controlling the number of revolution of the driving rolling rolls 1 so that its value is made less than the target value. In this way, piercing that makes biting height less than a certain value during rolling can be done and steady operation is possible.