A safety syringe comprises a barrel, a needle holder disposed on the barrel, a linking seat disposed in the needle holder, and a plunger rod disposed in the barrel. The barrel has a positioning annular groove. The needle holder has a first inner flange and a first positioning annular edge. The first positioning annular edge of the needle holder is engaged within the positioning annular groove of the barrel. The linking seat has an elastic wing and a first outer flange. The plunger rod has a second outer flange. By engaging the elastic wing of the linking seat with the second outer flange of the plunger rod, the linking seat may be moved in the direction away from the needle holder by the pulling force of the plunger rod and, during the movement, by engaging the first outer flange with the first inner flange of the needle holder, the needle holder together with the needle disposed on the needle holder may be pulled back into the barrel to enhance the safety after injection.一種安全針筒,包含有一筒體、一設於筒體之針頭座、一設於針頭座內之連動座,以及一設於筒體內之注射推桿,筒體具有一定位環槽,針頭座具有一第一內凸緣與一第一定位環緣,針頭座之第一定位環緣嵌卡於筒體之定位環槽內,連動座具有一彈性翼片與一第一外凸緣,注射推桿具有一第二外凸緣,藉由連動座之彈性翼片卡接於注射推桿之第二外凸緣,使得連動座在受到注射推桿之拉力時能朝遠離針頭座的方向移動,並且在移動過程中藉由第一外凸緣卡接於針頭座之第一內凸緣,用以將針頭座連同設於針頭座之一針頭一起拉回至筒體內,以增加在注射完畢後的安全性。20‧‧‧筒體21‧‧‧筒身22‧‧‧開口23‧‧‧針頭固定端部24‧‧‧定位環槽30‧‧‧針頭座32‧‧‧第一內凸緣33‧‧‧第二內凸緣34‧‧‧第一定位環緣40‧‧‧連動座43‧‧‧彈性翼片44‧‧‧第二定位環緣45‧‧‧第一外凸緣50‧‧‧注射推桿51‧‧‧推抵部52‧‧‧第二外凸緣62‧‧‧彈性塞體
