Abstract: A safety intravenous needle set includes needle hub holding a needle and an infusion tube at two opposite ends thereof, and a safety device, which includes a base block affixed to the needle hub, a recessed guard pivoted to the base block and having a retaining lug located on one of two opposing inner wall thereof. The recessed guard is biasable relative to the needle hub toward the medical needle to let the medical needle be forced over the retaining lug into the inside of the recessed guard and then retaining inside the recessed guard by the retaining lug, avoiding accidental needle stick injury after the service of the safety intravenous needle set.