To provide a high-lift rudder having a rudder shape and a structure which improves the propulsion performance and the steering performance by reducing the rudder area without degrading the propulsion performance in the straight movement with a simple configuration.

A flat bar 4 is connected to a rear end part of a rudder body 3 so as to be slightly protruded in the width direction from the rear end part of the rudder body 3, and the horizontal sectional shape of the rudder body 3 has a front half part of the streamline shape by a convex curve directed outward of the rudder, and a back half part of the follow shape inverted from the convex curve to a concave curve.