To provide a floater type hydrogen and oxygen production system, with which hydrogen and oxygen can be efficiently mass-produced utilizing natural energies of the vast sea, such as solar energy that falls onto the sea surface, wave power, tidal power and wind power.

A movable offshore floater is provided with a chamber 3 which receives solar power to generate steam by evaporating the seawater, a steam turbine 8 which is actuated by the steam from the chamber 3, and a generator 9 driven by the turbine 8. The steam that came through the turbine 8 is cooled by the seawater through a heat exchanger 10 to obtain plain water, which is then stored in a water storage tank 11. Thereafter, the plain water is dissolved into hydrogen and oxygen in a water electrolysis system 26 by the electric power from the generator 9, a wave power generator 5, a wind power generator 6 and a tidal power (water power) generator 7. Thus mass-production of hydrogen and oxygen can be efficiently carried out on the floater utilizing the natural energies.