PURPOSE: To provide a waterproofing treatment method for preventing the function of a lifesaving appliance from being impeded by water or humidity in its non-application such as during storage and also to simplify its operation in the life-saving device for a victim at sea which is automatically inflated by keeping contact with water.

CONSTITUTION: A hook 2 is sealed and fixed by one end of a water tight cover 3 and a part 7. And the other end of the water tight cover 3 is fixed to an emergency gas filling device main body by a rubber ring 4 for cover stopper. A trigger part having a quick water soluble holder is completely covered to prevent water entry. The water tight cover 3 is removed from the part of the rubber ring 4 by pulling the hook 2 in the arrow direction, exposing the inner part.