PURPOSE: To machine plural deep holes different from each other in position and angle in state where a work is once chucked.

CONSTITUTION: An X axis slide table 4 for indexing the longitudinal direction of a work 5 is provided on a NC rotary unit 2 for turning the work 5 to be machined and indexing the angle, and a chuck 6 and a tail stock 7 for indexing the phase of the work 5 and supporting the work are provided on the X axis slide table 4. Further, a supporting table 24 is provided in the neighborhood of the X axis slide table 4 so that it can be freely adjusted up and down, and a spindle unit 16 is provided on the supporting table 24 so that it can freely move away from or nearer to the work 5. A gun drill 22 is attached to the tip of a main spindle 20 of the spindle unit 16, and an automatic guide bush changer 25 for automatically selecting a guide bush 28 depending on the machining places of the work 5, is provided on the end part of the work 5 side of the supporting table 4.