To provide a monitoring system for an unmanned helicopter by which a cause of an abnormality is grasped quickly and accurately even during the flight of the unmanned helicopter and the work of the unmanned helicopter is carried out according to a plan by preventing a sudden stop of the work.

The monitoring system is capable of obtaining an in-flight self-diagnostic outcome from the unmanned helicopter 1. The monitoring system also obtains, from the in-flight unmanned helicopter, flight information related to the flight of the unmanned helicopter and work information related to the predetermined work carried out by the unmanned helicopter. The monitoring system displays predetermined instructions on a radio operating means 80 or sends a priority operation signal having priority to an operation signal, which is sent to the unmanned helicopter by the radio operating means for operation of the unmanned helicopter, to the in-flight unmanned helicopter based on the flight information and the work information.