The invention refers to an auto-injector and to a method for operating it, the auto-injector comprising of a tubular chassis a carrier subassembly comprising a tubular carrier slidably arranged in the chassis, the carrier containing a syringe with a hollow injection needle, a drive spring and a plunger for forwarding load of the drive spring to a stopper of the syringe a wrap-over trigger sleeve arranged over the distal end (D) of the auto-injector the trigger sleeve extending at least almost over the whole length of the auto-injector a control spring arranged around the carrier first interlock means for coupling a proximal end of the control spring to either the carrier for advancing it for needle insertion or to the chassis for needle retraction second interlock means arranged for releasing the drive spring for injection third interlock means arranged for coupling the chassis to the carrier for joint axial translation relative to the trigger sleeve and fourth interlock means arranged for coupling a distal end of the control spring to either the carrier for needle retraction or to the trigger sleeve otherwise.
