This paper proposes a new flexible fluid linear actuator we call Lambda-Drive. This actuator is composed of a flat-section tube and slider that keeps the tube lambda(Λ) shape. The tube is occluded at lambda shape point, and pressure in the tube provides force at the point, then slider moves by the force without high friction. The author shows how to move Lambda-Drive and measure the output force. The author applies the Lambda-Drive to a zip fastener and makes an active fastener that moves itself to pull up and pull off. This new actuator is very simple but high efficient and applicable to various equipments.