The present invention relates to a silencer duct for a ship's propeller using resonant barrels, wherein the ship's propeller is surrounded by the silencer duct so as to deaden underwater noises of various frequencies generated by the propeller, the duct being made into a cylindrical form to surround the propeller arranged in the side or rear part of the ship so as to guide the fluid direction as the propeller rotates, and the inside of the duct being provided with a plurality of resonant barrels for damping resonant frequencies arranged in the form of n×m (herein, n and m are natural numbers except 0) so as to damp the sound waves generated by the rotation of the propeller.