PURPOSE: To facilitate fitting to a work jig and jig maintenance and shorten a processing cycle time.

CONSTITUTION: A jig shift unit 13 is provided between a carrying in conveyor 11 and a carrying out conveyor 12, and a pair of work chucks 23a, 23b which are movable up and down, are provided at the upper part of the conveyors 11, 12, and this pair of work chucks are made capable of making a reciprocal movement between the 1st position where one work chuck 23a is at the upper part of a carrying in conveyor work taking out portion and the other work chuck 23b is at the upper part of a jig 16 that is at a work fitting position, and the second position where one work chuck 23a is at the upper part of the above jig and the other work chuck 23b is at the upper part of a carrying out conveyor work mounting position.