An authentication system that uses personal variable biometric information which changes according to times and environments, and an authentication method using the same are disclosed. The variable biometric information-based authentication system includes: a mobile terminal configured to generate information regarding an ID that intends to access a facility or information requiring an access authority, and to collect variable biometric information, such that information regarding the ID and the variable biometric information are stored all together; and a variable biometric information management server configured to, when the mobile terminal requests a login command regarding the ID, verify validity of the login command regarding the ID based on the variable biometric information. Accordingly, a real data value of collected biometric information is not used in the authentication procedure, and the authentication procedure is performed only by using a figure or a form of a graph indicating a variation in a specific section or a data arithmetic value obtained by performing a predetermined arithmetic operation with respect to the real data value. Therefore, even if the biometric information used in the authentication procedure is leaked, a damage resulting therefrom can be inhibited. In addition, since a security level of the authentication procedure can be selectively determined, the security of the authentication procedure can be enhanced by combining different types of variable biometric information or by combining variable biometric information of a plurality of users. In addition, as the security level of the authentication procedure is selectively determined, the authentication procedure can be diversely utilized in an entering authentication to a facility such as an office or school or secure authentication in financial services such as account transfer, payment, etc.