Abstract: A drug delivery device (1) is disclosed which comprises a housing (2) having a longitudinal axis, a piston rod (3), at least one resilient guide member (4) for guiding the piston rod (3) in a drug dispense operation and a cartridge holder (5) for receiving a cartridge (6), wherein the cartridge holder (5) is detachable from the housing (2). Furthermore the drug delivery device (1) is configured such that the resilient guide member (4) is allowed to relax when the cartridge holder (5) is detached from the housing (2).