a screw driver for use with electrical appliances under voltage includes a handle and a functional part with a shank and an end piece . the shank is designed to be partly covered by an insulating sleeve made of plastic . the end piece is insulated and connectable to said handle so that torque is transferable from said handle to said functional part . the handle is insulated from said shank . furthermore the screw driver includes a holding device which is connected to the handle and comprises a secured position and a released position . the holding device is manually operable between the secured position and the released position . in the secured position the holding device positively engages the functional part such that the functional part cannot be detached from the handle . in the released position the functional part is allowed to be detached from said handle .