PURPOSE: To efficiently cut a workplate by supplying a workplate piece formed with a longitudinal cutting saw onto the mounting table of a traverse cutting saw below a lifting device, and after traversely cutting it with the traverse cutting saw, mounting an edge strip from the lifting device onto the longitudinal cutting saw and cutting it, and then carrying it to the traverse cutting saw.

CONSTITUTION: A plate piece on a longitudinal cutting saw 10 is raised as an edge strip to a gathering position by a receiving device functioning as a lifting device 58. The workplate piece formed with the longitudinal cutting saw 10 is then supplied onto the mounting table 20 of a lateral cutting saw 12 below the lifting device 58 and laterally cut with the lateral cutting saw 12. The edge strips which are cut and gathered earlier than the workplate piece by cutting the workplate are then loaded from the lifting device 58 onto the longitudinal cutting saw 10 again and cut. Next, the edge strips are supplied to the mounting table 20 of the lateral cutting saw 12 by a carrying device and cut.