The invention relates to a activating mechanism for a medicament delivery device (1), wherein the activating mechanism comprises: - a cartridge (2) containing a dosage of a medicament, - a cartridge carrier (4) holding the cartridge (2) and comprising a distal carrier section (4.2), - a hollow injection needle (6) arranged within a distal end of the cartridge carrier (4) comprising an inner needle section (6.2) targeted inside the cartridge carrier (4), whereby the inner needle section (6.2) is spaced from the cartridge (2) in a distal direction (D) when the medicament delivery device (1) is in an initial position (P1), - a removable needle cap (5) to cover and seal an outer needle section (6.1) of the injection needle (6) that is targeted outside the cartridge carrier (4), wherein - at least the distal carrier section (4.2) is made from a resilient material so that the distal carrier section (4.2) is allowed to deform radially outwards when the needle cap (5) is removed and the cartridge (2) is moved in the distal direction (D). Furthermore, the invention relates to a medicament delivery device (1) comprising such a activating mechanism.
