The utility model relates to a negative pressure body fluid extracting syringe, in which the operator can operate the negative pressure body fluid extracting syringe with one hand, and can extract the body fluid of the detected person without pulling the pressure pushing piece.The negative pressure body fluid extraction needle cylinder comprises: a hollow cylinder body which can be combined with a needle body is provided with a first fixed hole and a second positioning hole, wherein the second fixed hole is close to the needle body； a push pressure piece is arranged on the cylinder body, and has a certain position part which can be clamped in the first and second positioning holes； and a bias device is arranged between the cylinder body and the push pressure piece for the purpose of The pushing piece moves in the direction of detaching from the cylinder body.By moving the pushing piece with the bias device, the operator does not need to pull the pushing piece, but only needs to hold the cylinder with one hand, so as to draw the body fluid of the tested person.一種負壓體液抽取針筒，操作者可以單手操作該負壓體液抽取針筒，且無需拉動該推壓件即可抽吸受檢測者之體液。該負壓體液抽取針筒包含：一中空圓柱體之筒體可結合針體，該筒體設有一第一定位孔與一第二定位孔，其中該第一定位孔靠近該針體；一推壓件設置於該筒體，且具有一定位部可卡制於該第一、二定位孔中；以及一偏壓裝置係位於該筒體與該推壓件之間，用以使該推壓件往脫離該筒體的方向移動。藉由該偏壓裝置移動該推壓件，操作者無需拉動該推壓件，僅需以一手扶住該筒體，即可抽吸受檢測者之體液。
