An automatic retractable syringe comprised of a syringe inside a compressed spring loaded locking safety sheath that moves into a protective position over the needle of the syringe that is triggered by the depression of the plunger, causing the positional locking mechanism to displace from its initial position and activate a compressed spring that expands, moving the locking safety sheath into its protective position and locks the sheath, preventing further movement of the locking safety sheath. An optional fusing system acts to permanently fix the locking mechanism in place to further secure the locking safety sheath in the protective position.
