PURPOSE: To perform drilling of a starting hole and a tapping operation in one reciprocating motion by performing the tapping while relatively moving a screw-feed shaft part relative to a nut member by means of a clutch means after the starting hole is drilled by rotating a shaft member and the nut member in the same speed.

CONSTITUTION: With a switch 2c, a clutch 7 ON, and with a clutch 8 OFF, a driving force of a motor 3 is transmitted to gears 9, 10, 11, 12, and a shaft member 4 is rotated in the same speed as the gears 11, 12 through a spline shaft part 4a. When a dog 2a strikes a limit switch 1d by rapid advancing traverse, a device body 2 is entered into cut-feed, and a starting hole machining unit 6a drills a starting hole in a work 13. At the same time when the drilling is completed, the dog 2a strikes a limit switch 1e to stop a feed motor 1c, and the motor 3 is switched to the slow speeds, the clutch 7 is turned OFF, the clutch 8 is turned ON, and the driving force of the motor 3 is transmitted to the gears 9, 11 to rotate the shaft member 4. When the gears 10, 12 become impossible to rotate, the shaft member 4 is screw-advanced because a screw-feed shaft part 4b is a female screw part formed in a nut member 5 integrally formed with the gear 12, and a tapping operation starts by a tapping part 6b.