PURPOSE: To achieve safety of work, preventing labor accidents due to clamping, by attaching a press plate to a supporting frame located farther from the surface of a table than the press plate and providing laterally a covering member close to the work space of the press plate.

CONSTITUTION: Covering members 47, 47 extend from both side plates (a), (a) of a supporting frame 37 toward the side surfaces of a press plate 40 so that the ends (b), (b) of the members 47, 47 terminate very close to the side surfaces of the plate 40 which is located at a press position or a store position. When the plate 40 is moved toward a work table 3 to press a workpiece W and fix it to the work table 3 or when said plate retreats from the press position and is stored in the frame 37, the members 47, 47 are always located adjacent to the side surfaces of the plate 40; therefore, the space between the plate 40 and the ends (b), (b) prevents the fingers of an operator from getting thereinto. As a result, even when an operator carelessly touches the frame 37, his fingers are prevented from being clamped.