A needle safety lock comprising a needle guard supporting member (14), and a needle guard (16) comprising an elongate member coupled to said needle guard supporting member and axially slideable with respect to the needle guard supporting member, and a cylindrical guard (20) having two open ends to enclose at least a portion of a needle； wherein the needle guard comprises a locking means to selectively secure the needle guard in a first locking position that is releasable or a second locking position that is non-releasable； and wherein when the needle guard is in the first or second locking position free axial movement of the needle guard is prevented.
