PURPOSE: To prevent generation of moises, vibrations, and the like by conducting boring by means of a cylindrical casing and an earth auger, conducting boring down to the support ground by means of the casing and the earth auger, and allowing a pile to fall into the bore.

CONSTITUTION: Around the bottom periphery of a casing 1 consisting of a steel pipe larger in diameter than the pile, there is fixed a bore broadening bit 2 larger in diameter than the casing 1. A pile is held between opposed hydraulic cylinders 7 arranged at the tip end of the casing 1. A bore is bored down to the support ground 13 by laterally rotating and oscillating the bit 2 about the axis of the casing 1 to bore the ground 12 and discharging the earth and sand present inside the casing 1 by means of an earth auger. Within the bore, a pile is suspended inside the casing 1 and allowed to fall by its own weight.