the invention relates to a safety syringe to prevent accidental puncture of attending medical personnel by an infected syringe needle . the safety syringe has an elongated tubular casing which receives the needle guard in a telescopical relationship thereto . at least on locking tab attached to the exterior of the needle guard extends outwardly through an opening formed in the casing , such that depression of the locking tab allows telescopical movement of the needle guard inwardly into the casing . a tension member retains the needle guard in its fully extended position unless the tension of the member is overcome by compression of the needle guard during injection or the drawing of a medicine . the tension member can be in the form of a coil spring surrounding the syringe barrel and urging against the needle guard and the flange plate of the casing , or in the form of an elastic resilient member attached under tension between the needle guard and the casing .