A rotor blade noise reduction system includes: a plurality of rotor blades; a plurality of first speakers disposed equidistantly on a first circumference which is opposed to one surface of a rotor blade plane; a plurality of second speakers disposed equidistantly on a second circumference which is opposed to the other surface of the rotor blade plane; at least one evaluation microphone configured to acquire noise generated from the rotating rotor blades and control sound generated from the first speakers and the second speakers; and an active sound suppression processor configured to input a plurality of first delay control signals corresponding to the first speakers, and to input a plurality of second delay control signals corresponding to the second speakers.