An access control method, comprising: performing a first access control operation for an access system by a first authentication subject, wherein the first access control operation includes performing (S115, S120) a first authentication (AU_1) for the access system; when the first access control operation is passed, transferring (S130, S135) second authentication information for a second authentication to the access system and a second authentication subject, receiving at the first authentication subject a result of a second access control operation (S140, S145, S150) for the access system which is performed by the second authentication subject that is separate from the first authentication subject; and allowing the access system to access the first authentication subject when the first access control operation and the second access control operation are passed, wherein the second authentication information includes an ID of the first authentication subject (ID 152) and an ID of the access system, receiving at the first authentication subject first authentication information for the first authentication (AU_1), wherein performing the first authentication (AU_1) comprises verifying whether a public key certificate of the second authentication subject (PKC), a public key certificate of the access system (PKC), and an electronic signature (SIGN) provided from the access system, which are included in the first authentication information, are valid, wherein the verifying whether the public key certificate of the second authentication subject (PKC) is valid includes comparing of a resultant value obtained by performing a hash operation of the public key certificate of the second authentication subject (PKC) with an authentication code stored in the first authentication subject, and wherein the first authentication subject verifies the validity of the public key certificate of the access system (PKC) using the public key certificate of the second authentication subject (PKC) that has already been verified, and wherein the electronic signature (SIGN) is generated by the access system after receipt of a random value generated by the first authentication subject, by using an electronic signature of the access system, and wherein the first access control operation further comprises confirming the number of times the access system accesses the first authentication subject, wherein when the number of accesses is equal to or less than a predetermined value and the first authentication (AU_1) is successful,, the second authentication information is transferred to the access system. performing a first access control operation for an access system by a first authentication subject, wherein the first access control operation includes performing (S115, S120) a first authentication (AU_1) for the access system; when the first access control operation is passed, transferring (S130, S135) second authentication information for a second authentication to the access system and a second authentication subject, receiving at the first authentication subject a result of a second access control operation (S140, S145, S150) for the access system which is performed by the second authentication subject that is separate from the first authentication subject; and allowing the access system to access the first authentication subject when the first access control operation and the second access control operation are passed, wherein the second authentication information includes an ID of the first authentication subject (ID 152) and an ID of the access system, receiving at the first authentication subject first authentication information for the first authentication (AU_1), wherein performing the first authentication (AU_1) comprises verifying whether a public key certificate of the second authentication subject (PKC), a public key certificate of the access system (PKC), and an electronic signature (SIGN) provided from the access system, which are included in the first authentication information, are valid, wherein the verifying whether the public key certificate of the second authentication subject (PKC) is valid includes comparing of a resultant value obtained by performing a hash operation of the public key certificate of the second authentication subject (PKC) with an authentication code stored in the first authentication subject, and wherein the first authentication subject verifies the validity of the public key certificate of the access system (PKC) using the public key certificate of the second authentication subject (PKC) that has already been verified, and wherein the electronic signature (SIGN) is generated by the access system after receipt of a random value generated by the first authentication subject, by using an electronic signature of the access system, and wherein the first access control operation further comprises confirming the number of times the access system accesses the first authentication subject, wherein when the number of accesses is equal to or less than a predetermined value and the first authentication (AU_1) is successful,, the second authentication information is transferred to the access system.