Abstract: A wave energy converting device disposed on the wave in the sea comprises a rotary shaft; a rotary hollow sleeve containing the rotary shaft therein; a plurality of partition walls for partitioning said hollow sleeve into a plurality of compartments; a plurality of radial plates each secured to the rotary shaft and said rotary sleeve to thereby form a plurality of water chambers; and plurality of first ports each formed in the rotary sleeve at the trailing end of each water chamber and adjacent to the radial plate corresponding to each water chamber.