PURPOSE: To improve welding efficiency for a workpiece by rotatably attaching a supporting body for the workpiece to a frame body having a central opening and respectively turning the workpiece through all directions around a transverse axis and a central axis.

CONSTITUTION: A cylindrical assembly (workpiece handling device) 180 is provided with the frame body 182 in which the central opening 184 is formed. The supporting body 200 for the workpiece (grid) 16 is turned to an optional angular position through 360 degrees around the central axis AC and attached to the frame body 182. Further, the frame body 182 is freely turned through 360 degrees around a Y axis with a driving device 194. The whole surfaces, i.e., six surfaces of the work piece 16 which is turnably supported on the supporting body 200 is welded with laser beams introduced from the opening of the frame body 182 by the mechanism system. Since the positioning of the workpiece 16 is simply facilitated, welding efficiency for the workpiece 16 is improved.