An automatic injector includes a cover extending along a longitudinal axis. A syringe for injecting a drug is arranged inside the cover, and includes a needle, a needle protector, a body, a plunger, and a rod for pushing the plunger into the syringe body, which is moved axially forwards by a resilient load force exerted by a first spring during an injection. The syringe also includes a tip for protecting the needle, which is axially movable about the needle and against a resilient load force exerted by a second spring between a forward position in which the tip surrounds the needle and a retracted position in which the needle is uncovered. A mechanism blocks the forward movement of the rod. The mechanism is deactivated as the tip is moved towards the retracted position and is reactivated during the injection when the tip is moved towards the forward position.