A safety needle for a needle tube that extends up and down and includes a needle holder and an outer cover. The needle hub includes a body portion, a constricted portion that protrudes coaxially upward from the main body portion and has an outer diameter smaller than the main body portion, and a shoulder portion that is located between the main body portion and the constricted portion, and An outer threaded portion projecting from an outer peripheral surface of the body portion. The outer cover is detachably attached to the needle seat, and has an inner screw portion disposed on the inner circumferential surface of the outer cover and screwed to the outer screw portion, and one inner screwing portion The upper portion of the portion and the needle holder are mutually engageable with each other and are limited to the engaging portion of the shoulder portion. The user needs to rotate the outer cover relative to the needle seat to move the outer cover away from the needle seat, thereby improving the safety in use.一種安全針具，適用於供一支上下延伸的針管安裝，並包含一個針座，及一個外蓋。該針座包括一個本體部、一個自該本體部同軸往上突伸且外徑比該本體部小的徑縮部、一個介於該本體部與該徑縮部相接處的肩部，及一個突出於該本體部的外周面的外螺接部。該外蓋可拆離地蓋合於該針座上，並具有一個設置於該外蓋的內周面並可供該外螺接部螺接的內螺接部，及一個位於該內螺接部上方並使該外蓋與該針座可相互嵌卡並限位於該肩部的嵌卡部。使用者需將該外蓋相對該針座旋轉才可將該外蓋移離該針座，提升使用上的安全性。
