A combined ampule-oneway injection syringe comprises a glass syringe body whose inner wall has been treated with a lubricant at a high temperature. One end of the body is permanently closed by a piston after a medicament has been located therein. The needle-side part of the syringe body is designed as a syringe cone having a peripheral annular groove. A connection piece including an inwardly directed nose-shaped part is undetachably engaged in the groove with clamping prior to the filling of the syringe body with medicament. A protecting cap is also located over the needle-carrying connection piece.