PURPOSE: To extract a stud bolt fixed to a screw hole in short period using an excitating machine.

CONSTITUTION: After a lubricating penetrant liquid is filled into the stud section of a stud bolt 3 by applying vibration onto it with a vipration exciting machine 14 provided at the top of the stud bolt 3 of which screw section 3a is fixed to a screw hole 2, a torque in the direction to loose the screw is applied to the stud bolt 3 to extract the stud bolt 3 from the screw hole 2. The vibration exciting machine 14 is operated to separate the screw hole 2 and the screw section 3a of the stud bolt 3 fixed to the screw hole 2. Thus the lubricating penetrant liquid filled into the stud section of the stud bolt 3 is penetrated between the separated screw hole 2 and the screw section 3a of the stud bolt 3, and the torque for extraction of the stud bolt 3 is reduced.