A driving device (1B) of a metering and mixing apparatus (1A) for multi-component substances, which driving device has at least two cartridge holders (2, 3) for holding interchangeable cartridges (2.1, 3.1), a discharging apparatus for the simultaneous discharging of the substance components from the cartridges by discharging pistons (11, 16) entering the cartridge holder or cartridges, wherein at least one discharging piston (11) has a thread which, by means of rotation, can generate a forward propulsion of said discharging piston, and a mixing apparatus (7) which is connected to component outlets, mixes the discharged substance components and discharges the latter in mixed form, with a gear unit (8) for connection of a drive motor (9) and a spindle-like discharging rod (5) of the discharging piston provided with the thread, a rear part of the longitudinal extent of which discharging rod has a spirally toothed, non-self-locking spindle section (5a) and, at the front end, an engagement element (5a) for engaging in the discharging piston, wherein the gear unit has a driven wheel (29) with an internal spiral toothing which is matched to the spiral toothing of the spindle section.
