PURPOSE: To allow a sheet material to readily perform vertical movement by providing a locking member for lowering a workpiece carrier body against spring force when the sheet material is conveyed to a press means by this carrier body with the carrier body pivotably supported through a parallel link by means of a supporting body.

CONSTITUTION: When a supporting body 104 is moved along the right side by a belt 110 nearly to the stroke end on the side of a supporting plate 101, the lower side section of a link 106 is abutted on a locking member 116 and a sheet material 1 is also fed into a press mechanism 30. After that, the link 106 is slanted by the locking member 116 against the spring force of a spring 111 accompanied with the movement of the supporting body 104 along the right side for lowering a carrier body 109. In the next step, when the supporting body 104 is moved to the stroke end on the side of the supporting plate 101, the carrier body 109 is lowered to the position of predetermined height for bringing the sheet material 1 on the carrier body 109 into contact with the top face of a die plate 302. At this moment, the belt 110 is made to stop.