This refers to an auto Injector (1) to administer a dose of liquid Medicine (m), which comprises: a tubular chassis (2) which is Telescopic in a tubular casing (12)； a subset of Carrier comprises a Carrier Tube (7) arranged on the slide Chassis (2) within the housing (12),The carrier (7) is adapted to contain a syringe (3) with a Hollow injection Needle (4), a Spring and a plunger Drive (8), (9) to forward the Spring load impulse (8) to (6) a Cap from the syringe (3),The syringe (3) can hold for the axial Translation together with the carrier (7)； a Shutter Button (13) with distally or at the side of the housing (12)； a Spring control (19) provided around the carrier (7)； a Control mechanism (24) extension of AG UJA to attach a proximal end of the Spring control (19) (7) either bearer to AVTo achieve the extension of the Needle or the chassis (2) for retraction of the Needle depending on the axial position relative to the carrier (7) and chassis (2)； a release mechanism (27) provided for the release of the Plunger piston (9) for injection when the carrier (7) almost Has reached at least one Extended proximal position fixer； a mechanism (18) and ready to connectL chassis (2) bearer (7) for the Co axial Movement with respect to the housing (12),The Fixator (18) provides a mechanism to decouple the chassis (2) of the carrier (7) after the actuation of the trigger Button (13) thus allowing the carrier (7) moves with respect to the chassis (2) to make the mechanism (24) control extension Needle Change and The proximal end of the control lever (19) to Carrier (7) for the extension of the Needle.A Control mechanism (25) willing to attach a syringe retraction of distal Spring control (19) (7) either bearer for retraction of the Needle or if not to the housing (12).La presente se refiere a un auto-inyector (1) para administrar una dosis de medicamento líquido (M), que comprende: un chasis tubular (2) que es telescópico en una carcasa tubular (12)； un subconjunto de portador
