The present invention discloses a data communication system, information treatment terminal, IC card, read/write machine and program. The data communication system is configured that the read/write machine, a integrated circuit card which implements wireless communication with the read/write machine without contact, and the information treatment terminal which connects to the integrated circuit card through wired interface can communicate with each other. The data communication system comprises: read/write machine with a read/write wireless control block; integrated circuit card with integrated circuit card wireless control block; and information treatment terminal with request receiving block, data memory block and data transmission block.