A case (2.1, 2.2), a case (2.1, 2.2) disposed driven carriage in (22), which is coupled to the drive carriage (22) and a plunger (11) auto-injector comprises (1) is described. The plunger (11) is adapted to releasably engage the needle retracting mechanism in the syringe (3). A drive carriage (22) Case (2.1, 2.2) to be to translating the distal direction (D) relative to the plunger (11) is allowed to engage the needle retracting mechanism, the drive carriage (22) The proximal By allowing translation in the direction (P) relative to the casing (2.1, 2.2), to engage the plunger (11) the stopper (5).
