SIRINGA

The invention relates to syringes and targets a syringe which enables the needle to be retracted automatically into a safe position after use, thereby also preventing it from being used again. According to the invention, the needle 5 is mounted on a needle-carrying plunger 2 which is supported so that it can slide in a leaktight manner inside the cylinder 1 of the syringe from a use position, in which the needle 5 projects out from the associated head of the cylinder 1 through a corresponding aperture 101, into a retracted safety position, in which the needle 5 is fully retracted inside the cylinder 1, elastic means 9 being provided which tend to push the needle-carrying plunger 2 into the retracted safety position of the needle 5 and locking means 7, 10 also being provided which are designed to retain the needle- carrying plunger 2 in the use position of the needle 5, against the action of the said elastic means 9, before and during use of the syringe, and which release the needle-carrying plunger 2 as soon as the injection has been carried out, allowing the needle 5 to be retracted into its safety position inside the cylinder 1.