According to the invention, an injection device (1) for administering a liquid comprises a pre-filled syringe (3) and a safety mechanism for providing needle safety for an injection needle (3.2) of the pre-filled syringe (3). The pre-filled syringe (3) comprises a barrel (3.1) containing the liquid, a stopper (3.5) translatably disposed within the barrel (3.1), the injection needle (3.2) attached to a distal end of the barrel (3.1). The safety mechanism comprises a substantially cylindrical housing (2) adapted to contain the pre-filled syringe (3), a plunger (4) connectable to the stopper (3.5) of the pre-filled syringe (3) and adapted to be translated in a distal direction (D) to expel the liquid through the injection needle (3.2), an energizable biasing means (6) arranged between the housing (2) and the pre-filled syringe (3), wherein the energized biasing means (6) is capable of biasing the pre-filled syringe (3) with respect to the housing (2) in a proximal direction (P) and a retaining mechanism for retaining the pre-filled syringe (3) with respect to the housing (2) in a first retracted position(R1), in an advanced position (A) and in a second retracted position (R2). The injection needle (3.2) is covered by the housing (2) in the first and second retracted positions (R1, R2) and projects distally from the housing (2) in the advanced position (A). The biasing means (6) is arranged in a non-energized state when the pre-filled syringe (3) is in the first retracted position (R1). The biasing means (6) is adapted to be energized upon translation of the pre-filled syringe (3) from the first retracted position (R1) to the advanced position (A) so as to bias the syringe (3) from the advanced position (A) towards the second retracted position (R2).La présente invention concerne un dispositif dinjection (1) destiné à administrer un liquide qui comprend une seringue pré-remplie (3) et un mécanisme de sécurité destiné à fournir une sécurité aiguille pour une aiguille din
