Abstract: A screwdriver comprising a handle with a central toothed recess formed thereon and a blind hole concentrically formed thereunder and having two retaining projections projecting therefrom, a speed change gear train disposed between the retaining projections, a spindle with a primary gear, constituting the gear train in part, integrally formed thereon and the lower end thereof received in the blind hole, a housing with an engaging device to engage with the driving gear of the gear train disposed around the gear train, a cover having a central bore formed therethrough screwed on the housing, and a sleeve of which the diameter thereof is less than the bore and of which the lower end engages with the upper end of the spindle and the upper end receives a shank which has a driving bit formed thereon. Thus, the rotation of the housing is transmitted to the driving bit via the speed change gear train with a higher speed.