PURPOSE: To prevent working efficiency from lowering in case of a working device failure by providing a retracting mechanism for drawing a pallet on a conveying device into a working device, between the conveying device and the working device.

CONSTITUTION: A workpiece is worked by a working device 11 while a pallet 21 on a conveying device 16 is being drawn aside. Respective control devices control to drive a conveying device 16, a lifter 14, a retracting mechanism 13 and the working device 11 independently. Accordingly, in case one of the working devices fails, for example, during workpiece working, the conveying device 16 need not be stopped. In this case, the conveying device 16 conveys another workpiece with the pallet 21 to another working device 11 for working. Also in this case, the workpiece in the failed working device 11 can be manually worked and thereafter returned onto the conveying device 16 by means of the retracting mechanism 13 and the lifter 14.