A self-controlled-closing dog muzzle comprising a dog neck harness, a mouth-closing muzzle, a drive apparatus, and a controller. The mouth-closing muzzle comprises a dog muzzle frame, a leash, a gear, and a gear base. The drive apparatus comprises an electric push/pull rod and a rack gear. The controller comprises a proximity switch and a battery. The dog neck harness is sleeved onto the neck of a dog. The drive apparatus, the leash, the gear base, and the controller are mounted onto the dog neck harness. A gear shaft of the gear is fittedly connected to the gear base, and the harness frame is fixedly connected to the gear, thus allowing the harness frame to sway as the gear rotates. The rack gear and the gear are meshed with each other. The gear is connected to a push/pull rod of the electrical push/pull rod. When the dog is away from an owner thereof, the controller controls the drive apparatus to drive the mouth-closing muzzle into swaying, thus allowing the muzzle of the dog muzzle to sway to a position at the mouth of the dog when the dog is about to bite someone, the muzzle isolates the mouth of the dog from the human body to prevent the dog from biting the human body, thus allowing effective prevention of dog bites, and at the same time, the muzzle does not obstruct the dog from opening the mouth thereof.Linvention a pour objet une protection de type muselière pour chien à fermeture automatique qui comprend un collier pour chien, une protection pour la fermeture de la gueule dun chien, un dispositif dentraînement comprenant une tige de traction électrique et une crémaillère, ainsi quun dispositif de commande comprenant un interrupteur de proximité et une batterie. La protection de type muselière pour chien à fermeture comprend une protection pour chien, une laisse à rallonge, un pignon et un support de pignon. Un collier pour chien est enroulé autour du cou du chien alors que le dispositif dentraînement, la laisse à rallonge, le support de pignon et le dispos
