A drive mechanism (11) for a delivery device comprising &mdasha drive member (17) for driving a piston rod (13) &mdasha moveable dose setting member (19, 35) being decoupled from the drive member (17) in a dose setting state the dose setting member (19, 35) being moveable in a drive direction in a dose delivery state, wherein the movement of the dose setting member (19, 35) is transferred to the drive member (17) and &mdasha dose control means (49) being coupled to the dose setting member (19, 35) by a rack-and-pinion means (51, 67) in such a manner that the movement of the dose setting member (19, 35) is transferred to a movement of the dose control means (49), wherein the movement of the dose setting member (19, 35) is stopped when the dose control means (49) reaches an end position.