A burglar alarm system using RFID(Radio Frequency Identification) technology is provided to quickly cope with a theft by outputting theft warning sound and light when an RF receiver does not receive information from a tag attached on an article or receives a radio wave from the place out of a predetermined range. A burglar alarm system(20) using RFID technology has a tag(11), an RF receiver(21), and an informing device. The burglar alarm system recognizes and memorizes information of the tag attached on an object(10) and determines a theft of the objects when a signal is not transmitted or received between the tag and the RF receiver, which continuously communicate with each other, or a radio wave is transmitted from the place out of a predetermined range.