An embodiment of a POS system according to the present invention stores log information and RAS information into a storage device (11) which stores an operating system, an application program and the like without being equipped with any non-volatile memories for storing the log information and the RAS information, wherein the log information is a record of a process, an operation and the like; and the RAS information is information pertaining to a hardware life-time. The POS device does not need to be equipped with a nonvolatile memory which is different from a storage device to store an operating system (OS), an application program and the like. Nevertheless the POS device is able to retain log information, RAS information and the like.