A long-term signature server in communication with a long-term signature terminal and a time stamp server, the long-term signature server comprising: signing target data acquisition means for acquiring (S115, S130) signing target data (XAdES); signature data transmission means for transmitting signature data (Signedlnfo) for electronic-signing signing target data (XAdES) which has been acquired to the long-term signature terminal; and signature value reception means for receiving an electronic signature value of the signing target data (XAdES) which has been generated using the signature data which has been transmitted from the long-term signature terminal; characterized by: time stamp acquisition means for acquiring a time stamp with regard to the electronic signature value which has been received, the time stamp being acquired from the time stamp server; a first signature data generation means for generating basic signature data (ES-XL) using, at least, the signing target data (XAdES) which has been acquired, the electronic signature value which has been received, the time stamp which has been acquired, a Certificate Revocation List and an Authority Revocation List; a second signature data generation means for generating first long-term signature data (ES-A) using, at least, the basic signature data (ES-XL) and a first archive time stamp (ATS) with regard to first original document data selected by a user which has been transmitted from the long-term signature terminal, wherein the first archive time stamp (ATS) is acquired by the time stamp acquisition means; and a third signature data generation means for generating second long-term signature data (ES-A) using, at least, the first long-term signature data (ES-A) and a second archive time stamp (ATS) with regard to second original document data selected by a user which has been transmitted from the long-term signature terminal, wherein the second archive time stamp (ATS) is acquired by the time stamp acquisition means. signing target data acquisition means for acquiring (S115, S130) signing target data (XAdES); signature data transmission means for transmitting signature data (Signedlnfo) for electronic-signing signing target data (XAdES) which has been acquired to the long-term signature terminal; and signature value reception means for receiving an electronic signature value of the signing target data (XAdES) which has been generated using the signature data which has been transmitted from the long-term signature terminal; time stamp acquisition means for acquiring a time stamp with regard to the electronic signature value which has been received, the time stamp being acquired from the time stamp server; a first signature data generation means for generating basic signature data (ES-XL) using, at least, the signing target data (XAdES) which has been acquired, the electronic signature value which has been received, the time stamp which has been acquired, a Certificate Revocation List and an Authority Revocation List; a second signature data generation means for generating first long-term signature data (ES-A) using, at least, the basic signature data (ES-XL) and a first archive time stamp (ATS) with regard to first original document data selected by a user which has been transmitted from the long-term signature terminal, wherein the first archive time stamp (ATS) is acquired by the time stamp acquisition means; and a third signature data generation means for generating second long-term signature data (ES-A) using, at least, the first long-term signature data (ES-A) and a second archive time stamp (ATS) with regard to second original document data selected by a user which has been transmitted from the long-term signature terminal, wherein the second archive time stamp (ATS) is acquired by the time stamp acquisition means.