Abstract: In order to provide a monitoring system for performing monitoring efficiently using a small number of cameras in accordance with a crowded degree in a target region, a monitoring system, comprising: a movable monitoring camera; and a controlling unit for controlling the monitoring camera, wherein the controlling unit detects a target object in a target region, calculates a crowded degree of the target objects in the target region, moves the monitoring camera to a position of the target object so as to monitor the target object if the crowded degree is small, and makes the monitoring camera round so as to monitor the target objects if the crowded degree is large is provided.