An unmanned helicopter includes a drive source, a tail rotor, a shaft unit that transmits a drive force from the drive source to the tail rotor, and an elastic member. The shaft unit includes a drive shaft, a transmission which transmits a drive force from the drive source to the drive shaft, and a transmittal portion that transmits a rotation torque from the drive shaft to the tail rotor. The drive shaft includes a first shaft portion and a second shaft portion. The elastic member is located between the first shaft portion and the second shaft portion.