To provide a hydrogen manufacturing facility on the ocean efficiently converting natural energy into hydrogen energy, reducing energy loss in storing/transporting hydrogen, and improving the efficiency of whole of the system.

The hydrogen manufacturing facility on the ocean is equipped with: a power generation means 2 performing power generation by utilizing natural energy such as wind power and sunlight or the like on a floating body 1 floating on the ocean; a seawater desalination means 3 desalinating the seawater; a water electrolyzing means 4 generating hydrogen by electrolyzing freshwater obtained by the seawater desalination means 3 by making the generation power obtained with the power generation means 2 as a power source; an organic hydride generation means 5 which hydrogenates hydrocarbon compound by reacting hydrocarbon compound and the hydrogen obtained by the water electrolyzing means 2 under the existence of a catalyst, and generates the organic hydride; and a storage means 6 storing generated organic hydride. The seawater desalination means 3 performs desalination by utilizing heat energy generated at the time of generating the organic hydride.