a die includes a stationary die , a movable die , which is opposed to the stationary die and reciprocatable in a first direction to change a distance between the stationary and movable dies , and a transfer mechanism , which transfers a workpiece , upon which plastic deformation work is performed between the stationary and movable dies , in a second direction crossing the first direction . the transfer mechanism includes a clamp portion , which clamps / unclamps the workpiece , a synchronizing member , which is engaged with the movable die to reciprocate in synchronization with reciprocation of the movable die , a clamp - unclamp operation converter , which converts reciprocation of the synchronizing member into clamping / unclamping of the workpiece by the clamp portion , and an advance - return operation converter , which converts reciprocation of the synchronizing member into advance - return operation of the clamp portion , whereby the clamp portion advances the workpiece in the second direction and is returned after advancement of the workpiece .