The present invention provides a blood sampling device 10 having body 12 having an opening 20 therein for receiving a retractable needle holder 14. A mechanism is provided for biasing the holder 14 and any needle contained therein to a position in which it projects from the body 12 such as to cause the taking of a sample of blood from a user. The mechanism includes a re-latchable spring biasing system.本發明係提供一種血液取樣裝置10,其具有本體12,該本體12在其中具有用於收納一可伸縮持針器14之一開口20。一機構經設置以用於將該持針器14及該持針器14所含之任何針偏置至其自該本體12突出之一位置,以便使得可自一使用者取得一血液樣本。該機構包括一可再閂鎖彈簧偏置系統。