According to the invention, an auto-injector (1) for administering a dose of a liquid medicament (M) comprises- a substantially cylindrical housing (2) arranged to contain a pre-filled syringe (5),- a syringe retainer (4) slidably arranged with respect to the housing (2) that mounts a pre-filled syringe (5),- a coupling shroud (6) slidably arranged within the housing (2) and releasably coupled to the plunger (9) and- a single drive means (8).The proximal translatory movement of the coupling shroud (6) with respect to the housing (2)- translates the syringe retainer (4) to expose the injection needle (12),- depresses the plunger (9) to expel the dose of medicament (M) and- advances a needle shroud (3) to a safe position (PS) to surround the injection needle (12) after the medicament (M) has been at least partially delivered. The coupling shroud (6) is decoupled from the plunger (9) at a pre-determined second position (II) defined by an aperture (2.3) formed into the housing (2).
