A method of load balancing by multiple cores in a multi-core-based load balancing apparatus comparing arriving packets with a signature is provided, and comprises first load-balancing first packets arriving on the multiple cores during a first period based on an arrival rate of the first packets, identifying a signature for the comparison, analyzing the first packets, determining at least one service type of the first packets, estimating a mean deep packet inspection (DPI) time corresponding to the determined at least one service type of the first packets, generating a load balancing rule using the estimated average DPI time, and second load-balancing second packets arriving on the multiple cores during a second period using the generated load balancing rule.