A biometric signature system, comprising: a biometric certificate storage module configured to store a biometric certificate generated based on biometric information on a user; a biometric information acquisition module configured to acquire new biometric information on the user; a biometric certificate generation module configured to generate a new biometric certificate based on the new biometric information; a biometric signature generation module configured to assign a biometric signature to the new biometric certificate based on the new biometric information; a biometric signature verification module configured to verify the biometric signature through use of the biometric certificate stored in the biometric certificate storage module; and a biometric certificate registration module configured to register the new biometric certificate with the biometric certificate storage module when the biometric signature is successfully verified, characterized in that the biometric information acquisition module is configured to acquire: first new biometric information, which is biometric information of the same body part and the same type as a body part and a type of biometric information used to generate the biometric certificate stored in the biometric certificate storage module; and second new biometric information, which is biometric information of one of a different body part and a different type from one of the body part and the type of the biometric information used to generate the biometric certificate stored in the biometric certificate storage module, wherein the biometric certificate generation module is configured to generate a new biometric certificate based on the second new biometric information, and the biometric signature generation module is configured to assign the biometric signature to the new biometric certificate based on the first new biometric information. a biometric certificate storage module configured to store a biometric certificate generated based on biometric information on a user; a biometric information acquisition module configured to acquire new biometric information on the user; a biometric certificate generation module configured to generate a new biometric certificate based on the new biometric information; a biometric signature generation module configured to assign a biometric signature to the new biometric certificate based on the new biometric information; a biometric signature verification module configured to verify the biometric signature through use of the biometric certificate stored in the biometric certificate storage module; and a biometric certificate registration module configured to register the new biometric certificate with the biometric certificate storage module when the biometric signature is successfully verified, characterized in that the biometric information acquisition module is configured to acquire: first new biometric information, which is biometric information of the same body part and the same type as a body part and a type of biometric information used to generate the biometric certificate stored in the biometric certificate storage module; and second new biometric information, which is biometric information of one of a different body part and a different type from one of the body part and the type of the biometric information used to generate the biometric certificate stored in the biometric certificate storage module, first new biometric information, which is biometric information of the same body part and the same type as a body part and a type of biometric information used to generate the biometric certificate stored in the biometric certificate storage module; and second new biometric information, which is biometric information of one of a different body part and a different type from one of the body part and the type of the biometric information used to generate the biometric certificate stored in the biometric certificate storage module, wherein the biometric certificate generation module is configured to generate a new biometric certificate based on the second new biometric information, and the biometric signature generation module is configured to assign the biometric signature to the new biometric certificate based on the first new biometric information.