An unmanned helicopter includes an altitude control device for giving a command of a collective pitch blade angle based on an altitude change rate command, etc., and performing altitude control of an airframe and takeoff device, upon reception of a takeoff start command from the ground, for causing the airframe to take off and climbing the airframe to a first altitude while increasing the collective pitch blade angle without performing the altitude control of the altitude control device and then causing the altitude control device to start the altitude control. The unmanned helicopter further includes descending device for causing the airframe to descend to a second altitude while changing descent rate command of the altitude control device and giving a descent rate command smaller than the descent rate command to the second altitude to the altitude control device for causing the airframe to descend from the second altitude to the ground.