PROBLEM TO BE SOLVED: To provide a driver of a medical screw which is excellent in operability and capable of extracting an engaging shaft part of a driver shaft tip from an engaged hole of the medical screw easily after the medical screw is screwed to a predetermined portion of a biological hard tissue.SOLUTION: A driver 100 comprises: a driver shaft 1 having an engaging shaft part 1a at the distal end a slide part 2 serving as a grip part 9 which is slidable forward and backward along the shaft 1 slide part temporary fixing means 3 for temporarily fixing the slide part 2 when it slides to a front end of a slide range, and releasing the temporary fixing of the slide part 2 when a force of a predetermined level or greater is applied thereto and a stopper 4 for abutting and stopping the slide part 2 when it slides to a rear end of the slide range. After screwing a medical screw 7, the temporary fixing is released by applying the force of the predetermined level or greater to the slide part 2, the slide part 2 is slid and collided with the stopper 4, and thus the engaging shaft part 1a is separated and extracted from an engaged hole 7a of the medical screw 7 by the impact force.SELECTED DRAWING: Figure 1
