PURPOSE: To simplify the device by bringing back up rolls into pressurized contact with groove rolls to transmit driving power and offsetting the centers of the groove rolls in the delivery direction of a wire from the centers of the back up rolls.

CONSTITUTION: The wire 35 is inserted between the plural groove rolls 25 having grooves 34 and the groove rolls 25 are driven to roll the wire 35. The groove rolls 25 are, thereupon, constituted as driven rolls. The back up rolls 13 are brought into pressurized contact with the groove rolls 25 to transmit the driving force. The centers of the groove rolls 25 are offset in the direction where the wire 35 is delivered from the centers of the back up rolls 13 in the rolling direction of the wire 35. The time for preparatory plane for the purpose of exchanging the rolls is drastically shortened in this way.