PURPOSE: To obtain both the continuity of working and the maintaining of machining precision in an index machine by providing a jig, with which the attaching angle of a workpiece can be changed, on a work table.

CONSTITUTION: A plurality of rotary jigs 4 each composed of a rotary part 1 in which a workpiece clamp 13 is attached to a base 12 having a rotary shaft 11, and a stationary part 2 to which the rotary shaft 11 is journalled, and to which the rotary part 1 can be fixed with a suitable angle, are arranged on a rotatable drive shaft is disconnectably coupled to the drive shaft of the rotary jig 4 on the center axis of the rotary shaft 11, around the rotary table. Further, a predetermined number of drive parts 3 which can rotate the rotary part 1 of the rotary jig 4 to a predetermined angle are arranged around the rotary table.