This propeller with a small duct is characterized by comprising the following: a propeller (10) which is attached to the stern of a ship hull (1); and a duct (20) attached in front of said propeller (10). Said propeller with a small duct is further characterized in that: the diameter (Ddin) of the duct (20) is 20% to 50% of the diameter (Dp) of the propeller (10); and the pitch (H) of the propeller (10) decreases progressively in the radial (R) direction, with the maximum pitch at the bases of the blades and the minimum pitch at the tips of the blades. By using an energy-efficient device that combines characteristics of large ducts and mid-sized ducts, adjusting the shape of the propeller (10), and disposing the small duct (20) near the front of said propeller (10), cavitation is reduced in ocean areas in which the degree of loading is increased, and interference from the small duct (20) is utilized to optimize the load distribution in the radial (R) direction of the propeller (10), which controls efficiency.