Our device uses the principle of the air bag and of grenade. First, in terms of air bag, we use the principle of expansion of at high speed. In terms of grenade, uses a principle of delayed-ignition fuse which makes time-lag explosion possible. Prior to using this it in the formation of a bar but it transforms into air tube in case of emergency. If the safety pin is removed the gas is created by delayed-ignition fuse and this flows into inner air tube and finally, the air tube swells. Through this mechanism, our device improved convenience of portablilty and storage. Not only that but with attachment of the rope allows to expand the rescuing range of drowing civilian far from the shore.