operating jig 14 as illustrated in fig1 the skin a or the like is incised and an upper end of the withdrawal guide pin 2 u2032 pierced into the bone c is inserted into the insertion hole 14 e of the withdrawal operating jig 14 by moving the withdrawal operating jig 14 downward along the withdrawal guide pin 2 u2032 the reverse internal thread portion 14 a of the withdrawal operating jig 14 is guided to the head portion 11 e of the screw 11 and brought into abutment with the reverse external thread portion 11 h in this case by using the withdrawal guide pin 2 u2032 as the withdrawal operating jig 14 and forming the top portion of the head portion 11 e into an arcuate shape the reverse internal thread portion 14 a is guided correctly to the reverse external thread portion 11 h subsequently the withdrawal operating jig 14 is rotated counterclockwise that is in a reverse thread direction by the grip portion 14 d the reverse internal thread portion 14 a of the withdrawal operating jig 14 is sufficiently screwed into the reverse external thread portion 11 h of the screw 11 and the withdrawal operating jig 14 is unified with the screw 11 when the withdrawal operating jig 14 is further rotated counterclockwise subsequently to the unification the screw 11 can be taken out by loosening the screw thread portion 11 b of the screw 11 with respect to the bone c.