A driving device for adjusting an activating element of a throttle, of a valve, of a connecting device, of a metering device or the like in particular in the field of oil and gas exploration with at least one rotary gear movably connected to the activating element and a gear arranged between the rotary gear and at least one motor. To improve such a drive device in that the structure is simple and compact and efficiency is increased wherein simultaneously high axial forces are avoided and only a small number of assembly parts are necessary, the gear unit comprises a reduction gear assigned to the rotary gear in particular the so called harmonic drive gear, and a spare gear assigned to the motor which is in particular self locking.