1. A method of monitoring a moving object within a predetermined monitoring area, the method comprising: detecting objects by scanning the monitoring area by an optical distance meter; identifying moving objects among the detected objects; setting, as a tracking target, among the identified moving objects, a moving object which is present in the monitoring area and which is newest identified; and automatically tracking the moving object which has been set as the tracking target, by an camera apparatus, wherein, when there are present a plurality of moving objects which are identified as being the newest, the tracking target is set in an order of starting from a moving object located the nearest to a border of the monitoring area, and the identified tracking target is automatically tracked, the setting and the automatically tracking being repeated for ail the identified moving objects; and wherein, when a response time is longer than a predicted time, the response time being a period of time required to automatically track a moving object newly set as a tracking target, the predicted time being a period of time necessary for the newly set tracking target to reach a priority monitoring object which is preset in the monitoring area, a priority monitoring area including the priority monitoring object is monitored, in fixed-point monitoring, at a wide angle by using the camera device.