To enable the unscrewing to be certainly done without hampering the rotation of the turntable, by the driving force from the die plate side that rotatably holds the turntable.

The unscrewing mechanism has the following: a first rotary body that is rotatably held on the die plate holding the turntable and rotated by rotation transmitted by a motor; a second rotary body that is linked so as to always rotate together with the first rotary body and so as to be movable in a predetermined amount to the axial direction against the first rotary body and that can take the position in which the detachable/attachable coupling part installed on the its end advances in the turntable by the driving force of the advance/retreat driving means and the position distant from the turntable; and a third rotary body that is rotatably held in the turntable and linked so as to rotate together with the unscrewing rotating part that rotates in the mold on the turntable and that has the detachable/attachable coupling part enabling rotation transmissive link with the detachable/attachable coupling part of the second rotary body.