A safety syringe comprises an injection barrel and a safety needle, in which the safety needle comprises a needle base, an injection needle, a needle sleeve, and an elastic member. The injection needle is combined with the needle base. The needle sleeve is combined with the needle base in a detachable manner and fitted onto the injection needle. The elastic member is disposed between the needle base and the needle sleeve. One end of the elastic member is connected with the needle base, and the other end is connected with the needle sleeve. When the needle sleeve is combined with the needle base, the elastic member is compressed； when the needle base is separated from the needle sleeve, the elastic member is elastically recovered to push the needle sleeve moving in a direction toward the tip of the injection needle, so that the needle sleeve may shield the needle tip to be prevented from exposure.一種安全注射器，包含有一注射筒與一安全針頭，其中，該安全針頭包括一針座、一注射針、一針套與一彈性件。該注射針結合於該針座，該針套以可分離的方式結合於該針座且套於該注射針上；該彈性件設置於該針座與該針套之間，該彈性件的一端連接該針座，另一端連接該針套。當該針套與該針座結合時，該彈性件受壓縮，當該針座與該針套分離時，該彈性件彈力回復，將該針套往該注射針之針尖的方向推動，使該針套遮蔽該針尖。藉此，避免針尖裸露。
