A printed sheet can be treated safely and conveniently in accordance with the degree of its content confidentiality as to secret information limited to distribution, duplication, etc. and non-confidential information. A sheet is provided with an IC tag and further machine identifiably expressed pattern information is added and printed as a key necessary to access the information stored at the IC tag to be a printed sheet. Thus, the secret information can be conveniently distributed together with information disclosed by printing while being kept safely in the IC tag, and cannot be accessed unless the printed sheet is available. Further, since the expressed pattern information is made to have an access level to secret information, the access to secret information can be set in accordance with the degree of confidentiality.