To provide a contactless IC tag for storing secret information for each of multiple stages of a life cycle from manufacture to disposal, and an access device for reading/writing information in secrecy from/to the contactless IC tag for each stage. A memory unit has stage storage areas as many as the stages. Each stage storage area is identified by a secret stage identifier. A controlling unit receives an access identifier from the access device in secrecy, via an antenna unit, a demodulating unit, and an instruction decoding unit. Upon judging that the access identifier properly identifies one of the stage storage areas, the controlling unit receives access information from the access device, and an inputting/outputting unit accesses the stage storage area based on the access information.