Described is an injection device (1) for administering a drug, the injection device (1) comprising a cartridge holder (2) adapted to receive a drug cartridge (3), a hollow injection needle (6) having a proximal tip (6.2) adapted to pierce a septum (4) of the cartridge (3) so as to establish a fluid communication between the cartridge (3) and the needle (6), and a cap (7) arrangeable over the cartridge holder (2) in a manner to cover the needle (6). In an initial state the cartridge (3) is arranged within the cartridge holder (2) with the septum (4) axially spaced from the proximal tip (6.2) of the needle (6). The cap (7) is adapted to move the needle (6) relative to the septum (4) for piercing it on movement of the cap (7) relative to the cartridge holder (2).