1. An activity map creating device that creates an activity situation of a moving object in a monitoring area, and outputs an activity map visualizing the activity situation of the moving object, the device comprising: a moving object detector that detects the moving object from a captured image of the monitoring area; a first activity value obtainer that obtains a moving object activity value indicating a degree of activity of the moving object for each of predetermined detection elements plurally divided from the captured image based on detection results of the moving object detector; a target area setter that sets a target area in the monitoring area in accordance with input operation by a user; a second activity value obtainer that aggregates, in the target area, moving object activity values for the respective detection elements obtained by the first activity value obtainer, to obtain a moving object activity value for the target area; a map generator that generates the activity map for the target area based on the moving object activity value of the target area obtained by the second activity value obtainer; and an output information generator that generates output information including a map image that displays the activity map generated by the map generator and overlapped on the captured image of the monitoring area.