Quantities of movements of human and matter within a detection area are detected, based on the read results of an ID holding unit arranged in the detection area or information obtained from a sensor arranged in the detection area. Parameters are decided in accordance with the detected movement quantity, and by using such parameters, whether the detecting object is within the detection area or not is detected, based on the read results of an ID holding unit attached to a detecting object. A stabilizing process is performed based on the detected movement quantities of human and matter within the detection area by employing such constitution. Thus, detection is stabilized without limiting using environment or using method.