The present invention periodically monitors the amount of packets flowing into a packet inspection apparatus, i.e., a load level, and compares the load level with a predetermined upper or lower limit value. Accordingly, the present invention blocks some of the packets or passes along some of the packets through the packet inspection apparatus when the load level exceeds a certain level, and thus the load controlling method and apparatus guarantees continuous operation of the packet inspection apparatus even in an overloaded state. In addition, the load controlling method and apparatus according to the present invention effectively selects packets to be blocked or passed without departing from the original functions of the packet inspection apparatus. The load controlling method and apparatus is configured simply so as not to additionally induce a load in the process of selection, and the load controlling apparatus selectively operates only in an overloaded state.