Retractable fluid collection device

The body liquid collecting device capable of automatically permanently retract (10) comprises: A shell of high-rise thin and an upper protective function (12), the shell of belt hole (15) is (14); The coaxial the piston (16), the piston with a a pin (32) needle handle (20) through the massage contact plate (26). The insertion sliding installed on the long and thin device or a shell, a of the axial of with a switch of rotating towards and front and direction and. Plunger is provided with an opening, comprising, along the axial edge and contact pin clamping hook circumference (68) surface of a sliding (66). When the piston is folded to move of the needle extended out the hole, the paw (48,50) and a piston fixed at the first position. The bias working is used for of the clamping on the needle pressing mechanism of front. A collecting pipe (72) is of the inserting rod part (40) and opening. A collecting specimen and taking out collecting pipe, of the piston cover (42) position, so the piston to transfusion to the second position so the piston of the first position to slide away from the needle clamp along the sliding contact surface. When the bias power surpasses remains of the sliding contact surface and confining pressure, and a clamping instantly permanently retracts to a piston the cavity in the space (17) and.