A medical delivery device (1； 10) comprises a rod element (3； 30), a dosage member (6； 60) and a lock mechanism. The rod element (3； 30) has a stem (31； 310) with a longitudinal axis (38； 380), a distal end and a proximal end. The dosage member (6； 60) comprises a delivery orifice (62； 620) and a chamber body (61； 610) with a distal end, a proximal end and a hollow interior. The stem (31； 310) of the rod element (3； 30) extends into the interior of the chamber body (61； 610) of the dosage member (6； 60) and the delivery orifice (62； 620) is arranged adjacent to the proximal end of the stem (31； 310) of the rod element (3； 30). In a dosing status of the medical delivery device (1； 10), the rod element (3； 30) is movable along its longitudinal axis (38； 380) relative to the delivery orifice (62； 620) of the dosage member (6； 60), such that a dosage chamber (611； 6110) is formed in the interior of the chamber body (61； 610) of the dosage member (6； 60) between the stem (31； 310) of the rod element (3； 30) and the delivery orifice (62； 620) which dosage chamber (611； 6110) increases when the rod element (3； 30) moves away from the delivery orifice (62； 620). The lock mechanism (530； 2410) is adapted for changing the medical delivery device (1； 10) from a lock status to the dosing status, wherein, in the lock status of the medical delivery device (1； 10), moving the rod element (3； 30) along its longitudinal axis (38； 380) relative to the delivery orifice (62； 620) of the dosage member (6； 60) is prevented.L'invention concerne un dispositif de dosage comprenant un élément barre et une enveloppe (4). L'élément barre comporte une tige ayant un axe longitudinal et un premier ensemble filetage. L'enveloppe (4) présente un second ensemble filetage (411). Le premier ensemble filetage de l'élément barre ou le second ensemble filetage (411) de l'enveloppe (4) comprend un filetage (411). Le premier ensemble filetage de l'élément barre et le second ensemble filetage (411) de l'env
