PURPOSE: To improve thrust in the flight direction by providing a main rotor which rotates roughly in a horizontal plane, and a tail rotor having a cyclic control mechanism which rotates roughly in a vertical plane.

CONSTITUTION: A single rotor helicopter has a main rotor 2 roughly at a top part of an airframe 1, and a tail rotor 3 to offset torque of the main rotor 2 is provided on the side of a rear part. The main rotor 2 is provided with a cyclic control mechanism (a mechanism to change a pitch angle of a rotor blade every moment in accordance with a rotation position). In this helicopter, a cyclic control mechanism which rotates roughly in a vertical plane is provided on the tail rotor 3 in which a pitch angle conventionally has been controlled by a collective control mechanism, thereby conventional partial force of thrust backward is eliminated to increase thrust in a flight direction.