To improve the cycle time of the whole production line system by shortening the stand-by time of a pallet carrier at an automatic set-up station.

A transfer device 8A provided with a plurality of transfer tables 9a, 9b moving in the lateral direction is disposed in a position along the pallet carrier 3 for transferring a pallet 6 with a jig. The pallet 56 with the jig holding a workpiece W to be machined is placed on the transfer table 9b beforehand from an attaching/detaching table 22. When the pallet 6 with the jig holding the machined workpiece W is transferred to the transfer table 9a by the pallet carrier 3, the pallet carrier 3 immediately moves to the side of another transfer table 9b to transfer the pallet 6 with the jig holding a workpiece W to be machined, to a pallet stocker 5. Since the pallet 6 with the jig is immediately transferred, the stand-by time of the pallet carrier 3 at the set-up station 4A is shortened.