The recent development of mobile network technology resulted in commercialization of Long Term Evolution (LTE) network, opening the era when data can be processed at high speed even in the mobile. But a new authentication key must be created during the handover in the LTE network environment. In this case, the authentication process is performed by handover and therefore, authentication cost and delay time are caused. In this paper, we propose an efficient key caching handover technique of simplifying the authentication process by reusing the stored authentication key if old Mobility Management Entity (oMME) stores the authentication key for a certain period of time and returns it to oMME within Life Time of the authentication key when User Equipment (UE) is handed over from oMME to New Mobility Management Entity (nMME).