The invention relates to a safety needle assembly for injecting a fluid into a human body comprising a cylindrical housing with a bottom surface supporting a needle cannula and a shield telescopically movable relative to the housing. A spring located within the housing urges the shield in a distal needle covering direction and a locking member also provided inside the housing moves simultaneously with the shield during injection and automatically locks the shield in a position where the sharp end of the needle cannula is concealed thereby irreversible immobilizing the safety needle assembly.
