The structure of a blood collecting pen mainly comprises a tube body, a seat, a pull piece, a movable seat, a set of bodies and a blood collecting needle. Before collecting blood, the blood collecting needle is inserted on the movable seat, and the pull piece is pulled backward to drive the movable seat to the position of firing. At last, press the button to instantly send the blood collecting needle, so that the blood collecting needle can be punctured into the skin to achieve the goal of obtaining blood And the degree of penetration of blood sampling needle into the skin can be controlled by adjusting the cuff.一種採血筆之結構，其主要包括有一管體、一座體、一拉件、一活動座、一套體與一採血針，在採集血液前，將採血針插置於活動座上，並將拉件向後拉以帶動活動座位於擊發之位置，最後按下按壓鈕以瞬間即發採血針，以使採血針刺入皮膚進而達到取得血液之目的，並且可藉由套體之調整來控制採血針擊發時刺入皮膚之程度。
