PURPOSE: To make a compact machine and to reduce its cost by opposingly fixing a pair of center-boring units and setting the axial line of a workpiece in alignment with a line which connects the tops of the units to each other to set a removable clamp jig in a direction across the line.

CONSTITUTION: The clamp part 28 of a clamp jig 27 supports a workpiece W, and by driving a working unit 25 on one side the workpiece W is moved up and down by a hydraulic cylinder 31, and its one side end face is also cut to the desired size by a milling cutter 2. Similarly the other side and face of the workpiece is cut by the milling cutter 3 of a working unit 26 to cut the total length of W in good accuracy. Then, the workpiece W is moved by a clamp jig 27 onto the axial line of drills 4, 5 of working units 25, 26, respectively, then center holes are drilled on its both end faces. By this constitution the structure and the control of the machine becomes simple, and machine can be compact and the installing cost can be reduced.