<p>A showcase (300) has reading means for reading an RFID tag (12) attached to a merchandise article (10) and transmits detected information to a store computer (100). The store computer (100) has receiving means (120) for storing stock information received from the showcase (300) into a database (150) and also has theft determination means (170) for determining an occurrence of a theft according to a predetermined rule with reference to stock information stored in the database (150) and based on information on a merchandise article taken out of the showcase (300).</p>
