The invention discloses a safe self-destroying medical injector, which comprises the following parts: hollow cylinder, snap coil, needle seat and core bar, wherein the plug is assembled in the core bar head; a coil of flute is set in the head of cylinder; the boss is set on the top of core bar with upper round boss and lower round boss under the boss; the easy-breakpoint is set under the lower round boss; the needle seat is composed of separable conical seat and support seat with an 'O' rubber ring between the excircle of conical seat bulk and cylinder; two through-grooves of central symmetry are set under the conical seat, which sets two bosses of central symmetry between two through-grooves; the boss snaps the flute on the cylinder; the flute is set on the inner hole bottom of conical seat. |