PURPOSE: To process a work using a single jig by moving an eccentrically locational pin and an eccentric guide bushing through eccentric rotation in correspondence to the work being different only in the overall length, performing thus locational alignment, and allowing other clamp device etc. to be used as they are.

CONSTITUTION: An eccentric locational pin 11 is inserted in the reference hole in a work, and its different parts are clamped by a clamping mechanism 7. At the same time, an eccentric guide bushing 15 to guide a tool is located in place. These motions are conducted simultaneously by a single moving mechanism. In the case of processing works different only in overall length, the eccentric locational pin 11 and eccentric guide bushing 15 are rotated by a driving mechanism, and they are located in the position to suit the length of the work. Then the moving mechanism moves simultaneously the eccentric locational pin located rotationally, eccentric guide bushing, and clamping mechanism, to perform location and clamping of works having different overall lengths, followed by processing as desired.