Abstract: A rotor blade for a rotary wing aircraft, which rotates about and is combined with a rotation shaft of the rotary wing aircraft. The rotor blade includes a body combined with the rotation shaft and including a leading edge that is a front edge in a direction of rotation; and a plurality of deformable protrusions formed on the leading edge of the body in a radial direction of rotation, and deformable between a first shape protruding forward in the direction of rotation and a second shape not protruding forward in the direction of rotation such that BVI noise generated when a vortex formed near a blade tip collides with the rotor blade is selectively reduced whenever necessary. The deformable protrusions are formed in a region from a point spaced apart from the rotation shaft by 75% of a radius of rotation to a point spaced apart from the rotation shaft by 90% of the radius of rotation.