Hydrogen gas is added into living organism applicable fluid substantially without changing constituents of the living organism applicable fluid by reacting a hydrogen generating system and a generating-purpose water, wherein the hydrogen generating system contains metal aluminum, which is a food additive, as a hydrogen generating agent and calcium oxide or calcium hydroxide, which is also a food additive, as a hydrogen generating reaction accelerator such that the hydrogen generating agent and the hydrogen generating reaction accelerator are adjacent to each other.
