This paper proposes an optimum seaport container terminal which reduce external truck's waiting time at gate. In the seaport container terminal, a recent rapid growth of container volumes and vessel size affects smooth container-handling operations. As a result, it leads to road congestion in front of the gate. In this paper, we apply the discrete event system as a simulation model of the container terminal and analyze the cause of the truck's delay. Although there are numerous planning and decision problem (for example berth allocation problem), we deal with the container-stacking problem and the storage machine scheduling problem. The goal of our study is to reveal which dispatching rule is the best trade-off between performance and cost for each container terminal.