A communication system, a communication method and program thereof capable of easily constructing a system in which communication between an IC tag and a mobile information terminal having a built-in or externally-attached reader/writer is used. URL information in the Web page for disclosing personal information stored on the IC tag is read by the reader/writer and the information is accessed. A security system is provided in which an alarm is performed for preventing losing an article according to the communication state between the IC tag and the reader/writer, and if an article is lost, its position information can be checked by a mobile information terminal or another terminal device.