Disclosed is a drive mechanism for an injection device for setting and dispensing of a dose of a medicament, the drive mechanism including an inner body fixable inside a housing of the injection device, the inner body including an elongated shaft extending in an axial direction and having an outer thread, a tubular-shaped display member having an inner thread engaged with the outer thread, and a dose member axially displaceable between a dose setting position(S) and a dose dispensing position (D) relative to the display member. The display member includes at least one blocking member movable in axial direction (z) between a blocking position (B) and a release position and engageable with a blocking thread on the outer circumference of the inner body.

A cartridge holding unit includes a cartridge container forming an outer surface of the cartridge holding unit and having an inner space, and a cartridge holder forming a tube-shaped holding section arranged in the inner space of the cartridge container. The cartridge holder firmly holds a cartridge in parallel with the cartridge holder and the cartridge holder and the cartridge container are firmly coupled to each other in respective axial orientations.