The present invention relates to an independent power generating method using water pressure and vapor, and a generating device thereof, which: sequentially circulate water by using a head drop of water and high-pressure vapor so as to continuously generate power, and generate power with a natural head drop caused by the gravity of water and, simultaneously, produce power with vapor; and naturally increase, condense, and reuse the vapor so as to hardly waste water resources such that power can be efficiently generated by efficiently rotating water wheels connected to an electric generator.