This refers to an auto Injector (1) to administer a dose of liquid Medicine (m), which includes: An elongated housing (12) ready to be Sustained by a user a Telescopic tubular chassis (2) in the housing (12) and biased against the casing (12) to Excel The casing (12) a syringe (3) with a Hollow injection Needle (4),A Drive Spring (8) and a piston (9) to forward the Spring load impulse (8) to (6) a Cap from the syringe (3) a Shutter Button (13) with distally in or on the casing (12),When the Shutter Release Button (13) is coupled to the housing (12) initially a way to Excel in distally from the housing (12) and coupled to the chassis (2) in a manner that prevents the Shutter Release Button (13) of the housing (12) and prevent this the accionamie Nto the Shutter Release Button (13) at an initial positionIn the housing (12) is provided for moving proximally (P) against the bias with respect to the chassis (2) when the chassis (2) is pressed against an injection site, moving with it also the trigger Button (13) by dropping the connection with the chassis (2) for PE Rmitir actuation of the trigger Button (13),When the Shutter Release Button (13) is provided for locking in a more proximal to the Drive.La presente se refiere a un auto-inyector (1) para administrar una dosis de un medicamento líquido (M), que comprende: una carcasa alargada (12) dispuesta para ser sostenida por un usuario un chasis tubular (2) telescópico en la carcasa (12) y predispuesto contra la carcasa (12) para sobresalir de la carcasa (12) una jeringa (3) con una aguja de inyección hueca (4), un resorte de impulso (8) y un émbolo (9) para reenviar la carga del resorte de impulso (8) a un tapón (6) de la jeringa (3) un botón disparador (13) dispuesto en sentido distal en o sobre la carcasa (12), en el que el botón disparador (13) se acopla inicialmente a la carcasa (12) de una manera para sobresalir en sentido distal desde la carcasa (12) y enganchado al chasis (2) de una manera que impide que el botón
