When an unmanned aerial vehicle flies in accordance with a planned route that is set in advance on the basis of a position of a GPS receiver measured by a measurement unit and the measurement accuracy detected by a measurement accuracy detection unit has decreased to be less than a predetermined value, a flight control unit performs control so that the unmanned aerial vehicle flies along a route different from the planned route. Moreover, when flying along the planned route lowers the measurement accuracy, the unmanned aerial vehicle is caused to fly along the route different from the planned route. Therefore, the flight can be continued while the position is measured with the measurement accuracy secured.