Abstract: A driving device includes a driving shank, a magnetic member mounted in the driving shank, a stop ring secured in the driving shank to stop the magnetic member, and an elastic member biased between the driving shank and the magnetic member. The driving shank has a first end provided with a mounting post and a second end formed with a mounting hole and a receiving chamber. The stop ring has an inner wall formed with a through hole and an outer wall provided with a toothed portion engaging a peripheral wall of the receiving chamber. The magnetic member has a peripheral wall formed with a stop flange that is movable to abut the stop ring. Thus, the elastic member provides a buffering effect to the magnetic member to reduce the pressure applied on the magnetic member.