PURPOSE: To raise the efficiency of boring work by a method in which an excavating tip provided to the tip of a boring machine is rotationally driven by a driver set on the tip of the device.

CONSTITUTION: Cylindrical excavating tips 43 with cutting edges 43a are fixed to the tip of a guide tube 41, and the mouth metal 47 of the tube 41 is provided with the stator 52 of a supersonic motor 51 as a driver to rotationally operate the tips 43. The tips 43 are connected to the rotor 53 of the motor 51 and rotationally driven by the rotor 53 to be driven by the stator 52. Since the needs for transmitting rotation force through the tube 41 to be touched by the surrounding soil can be eliminated, the excavating function can be raised without receiving frictional force.