PURPOSE: To provide an auger/pile driver automating the turn action and stop action of a leader and capable of finely adjusting the turn position of the leader.

CONSTITUTION: A motor with reduction gear 12 having a pinion gear 13 is fitted to a leader bracket 2, and a ring gear 14 meshed with the pinion gear 13 to turn a leader 4 is provided on an upper turn seat 3. A leader turning device provided with a cylinder 24 releasing the insertion of a stop pin 22 into the positioning hole 2a of the leader bracket 2 is provided on a turn stopper device 20. A guide rail 31 is provided at the fitting position of the turn stopper device 20 on the upper turn seat 3, and two cylinders 32A, 32B capable of optionally moving the stopper pin 22 within the range of adjacent positioning holes of the leader bracket 2 along the guide rail 31 are provided on both sides of the turn stopper device 20.