PURPOSE: To automatically eliminate difference in parallellism of a work even when the difference in parallellism of the work to an NC processor exceeds a predetermined value that can be processed by providing a work re-inputting means for once cancelling the positioning of a pallet to the NC processor when the difference in parallellism exceeds the predetermined value, and for carrying out relocation.

CONSTITUTION: A pallet 2, to which a work is loaded and fixed, is positioned at a processing position of an NC processor 4 by moving a positioning pin 41 upward and fitting it to a taper hole 21. Positions of reference holes 11, 12 formed on the work 1 are measured by a probe 51, and when difference in parallellism of the work l to the NC processor 4 exceeds a predetermined value, the positioning for the pallet 2 is carried out again by moving the positioning pin 41 upward again after it is once moved downward, and the difference in parallellism of the work 1 is thus eliminated.