Abstract: Shock caused to a clutch mechanism of an electric screw driver is minimized by bearing members, adjacent to upper and lower clutch members, which are provided with bearing distal ends which contact one another when one of the clutch members moves toward the other clutch member by means of the biasing force of an adjustment coil spring. The bearing distal ends prevents the clutch members from impacting with one another. Resilient convex discs which bulge in opposite directions are provided adjacent to one of the bearing member to absorb shock caused to the bearing members. Limitedly movable engaging members are provided in the clutch members to minimize localized wear of the engaging members.