The present invention relates to drug delivery devices. The drug delivery device according to the invention includes a housing with a needle holder suitable for attaching a needle unit to the housing at the distal end, and a cap being capable of covering the distal end of the drug delivery device and comprising a retaining member capable of securing the cap by engaging with the housing, the retaining member is prevented from engaging with the housing with the needle unit being attached to the needle holder. Furthermore, using a cap for covering the distal end of the drug delivery device is disclosed.The present invention relates to drug delivery devices. The drug delivery device according to the invention includes a housing (10) with a needle holder (24) suitable for attaching a needle unit (20) to the housing (10) at the distal end (22), and a cap (30) being capable of covering the distal end of the drug delivery device (5) and comprising a retaining member (32) capable of securing the cap (30) by engaging with the housing, the retaining member is prevented from engaging with the housing (10) with the needle unit (20) being attached to the needle holder (24). Furthermore, using a cap for covering the distal end of the drug delivery device is disclosed.La présente invention concerne des dispositifs dadministration de médicament. Le dispositif dadministration de médicament selon linvention comporte un boîtier (10) avec un porte-aiguille (24) permettant la fixation dune unité daiguille (20) au boîtier (10) à lextrémité distale (22), et un capuchon (30) qui permet de recouvrir lextrémité distale du dispositif dadministration de médicament (5) et qui comporte un organe de retenue (32) capable de fixer le capuchon (30) en étant en prise avec le boîtier (10) lorgane de retenue ne peut pas venir en contact avec le boîtier (10) lorsque lunité daiguille est fixée au porte-aiguille (24). Linvention concerne également lutilisation dun capuchon pour recouvrir lextrémité distale
