An injection device (22) is equipped with a compartment articulated with reference to the device to receive a syringe (10) with staked needle (18) protected by a protection cap (20) coupled with the syringe, the compartment being susceptible to evolve from a first open position for the insertion and the removal of the syringe, and a second closed position for the realization of the injection. The device includes a detachment system intended to cooperate with the cap of the syringe to decouple it from the syringe, the detachment being conditioned by the passage of the compartment to its second position. Furthermore, the passage of the compartment from the second to the first position is conditioned by the coupling of the cap.
