Abstract: An automatic machining apparatus includes a rack for storing workpieces mounted on pallets, setting stations for setting the workpieces on the pallets, processing machines for processing the workpieces according to specified processing information, and a stacker crane for transporting the workpieces on the pallets between the rack and setting stations and between the rack and processing machines. The entire apparatus is operable under control of a main controller, with the processing machines controlled by an auxiliary controller. Each pallet carries an IC card for storing information on treatment done to the workpiece mounted thereon. The main controller includes a first communicating device for writing the information on treatment into the IC card. The auxiliary controller includes a second communicating device for reading the information on treatment from the IC card.