Disclosed is a self-destructing syringe, comprising an outer casing, a core bar, a piston, a conical head component, a syringe needle and a protecting jacket. The syringe needle is fixed in the conical head component, and the conical head component consists of a threaded conical head, a sealing ring, a transition part and a hollow wedge. The protecting jacket is put around the syringe needle and is movably connected to the needle base of the syringe needle the conical head component is fixed in the inner cavity at the front end of the outer casing the piston is installed on the core bar the main part of the core bar is sheathed inside the outer casing and the front end of the core bar is inserted into the conical head component and is able to make the syringe needle return inside the outer casing.