The needle protector (22) is connected to a support (2) with an inner chamber (27) to receive a carpule (1) of a liquid medication to be injected. The needle (30) is attached to the support in line with the axis of its chamber, while the support has a series of hooks (32) forming a cage (31) that engages elastically round the neck of the carpule. There is also a pre-compressed spring (24) between the support and protector that pushes the protector towards its deployed position, and the end of the support has a thrust collar (26A) for the spring.
