FRAUDULENT-PURCHASE ALARM SYSTEM, FRAUDULENT-PURCHASE ALARM METHOD, AND RECORDING MEDIUM

摘要

A fraudulent-purchase alarm system for issuing an alarm about a fraudulent purchase of an article for sale includes: a first storage that stores a price of the article for sale; a second storage that stores purchase amounts of articles for sale purchased by a user of the fraudulent-purchase alarm system; a third storage that stores an upper limit of a total purchase amount of the user; and a controller that, upon receiving a purchase request to purchase the article for sale and identification information about the user, refers to the first to third storages to issue an alarm about a fraudulent purchase if a sum of the purchase amounts of articles already purchased by the user identified by the identification information and the price of the article for sale indicated in the purchase request exceeds the upper limit, wherein the controller lowers the upper limit if a predetermined condition for preventing a fraudulent purchase is met.