Without a proper protection mechanism for the signaling messages to be used for the mobility support in the Proxy Mobile IPv6 (PMIPv6), it is also vulnerable to several security attacks such as redirect attack, MITM (Man-In-The-Middle) attack, replay attack and DoS (Denial of Service) attack as in Mobile IPv6. In this paper, we point out some problems of previous authentication mechanisms associated with PMIPv6, and also propose a new fast and secure authentication mechanism applicable to PMIPv6. In addition, it is also shown that the proposed one is more efficient and secure than the previous ones.