When a document creation unit 1 is started, it calculates a hash value of each software piece therein and stores the hash value in a hash value holder 71 and a measurement log document holder 44. The document creation unit 1 accesses a time distribution unit plural times to receive time information therefrom, and records the time information in a log document and a measurement log document. The document creation unit 1 transmits the log document, the measurement log document, and digital signature-embedded hash value information (measurement auxiliary document) in a tamper-resistant device 63 to a document reception device. The document reception device verifies matching of the hash values or digital signature in the document group, confirms software operating environments in the document creation unit 1 from the hash values, and determines whether the time information is correctly managed within the unit 1.