Information processing device, display method, and program storage medium for monitoring object movement

To display with a display mode with which an analyst may easily ascertain actions (movements) of objects being monitored, provided is an information processing device, including a sensing and a display control unit. The sensing unit classifies, based on information relating to movements of objects being monitored, a plurality of objects into set movement paths. The display control unit controls a display such that the movements of the objects are displayed in a display screen of the display with an arrow in each set movement path. The axis of the arrow which is displayed in the display has a thickness according to the number of objects which are classified in the corresponding movement path, has a shape according to the trace of the objects which are classified in the corresponding movement path, and furthermore, the direction indicated by the arrow represents the direction of progress of the objects.