Abstract: A safety syringe includes a glass syringe body, a plunger slidable inside the syringe body and provided at the rear with a manually operable stem, an injection needle mounted at the front end of the syringe body, a sheath mounted integrally on the syringe body, a sleeve mounted slidably on the sheath to pass from a retracted use position to an advanced safety position, in which the needle is protected by the sleeve, locking elements mutually provided in the sheath and in the sleeve to lock the sleeve in position when it is in the retracted use position and in the forward safety position, and operating elements integrally mounted with the stem of the piston to cooperate with locking elements so as to allow movement of the sleeve from the retracted use position to the advanced safety position.