Software-defined networking (SDN) is a new network model, and it changes the current limit network facilities. In SDN, the control logic is separated from network devices such as routers and switches. Accordingly, network devices only need to transfer data (data layer), while the control logic is handled by a central controller. In this paper, we propose a dynamic load-balancing mechanism to reduce response time by adjusting rules in the SDN flow table. Our scheme can adjust the binary tree depending on the load on each server. When a server is out of capacity, it can dynamically transfer excess traffic load to servers with less load. Simulations show that our scheme not only balances server load but also maximizes server usage.