A portable personal self-operating life tube is disclosed, in which when a user is drowned in water due to a marine disaster or a fire and sinking of a ship, it automatically operates, so the user can save his life by just wearing the tube, and the tube is able to keep a user's a body temperature until a rescue comes after the tube is expanded along with the above features, and a life tube can be easily used without a particular care by improving the problems found in a conventional art in which a user feels bad when wearing a life tube since a conventional life equipment is not customized, and it is not portable and is not easy to use.