The present invention relates to a propeller duct for a ship reducing a vortex of a rudder for a ship. More specifically, the duct for a ship is configured to improve a thrust by controlling the direction of a slipstream introduced to a propeller. To achieve the purpose as described above, the present invention relates to the duct installed in a stern and rectifying a fluid entering the propeller. The duct comprises: a curved duct frame; outer wings connecting both ends of the duct frame and the stern and twisted in the longitudinal direction; and inner wings connecting the inside of the duct frame and the stern and twisted in the longitudinal direction.
