There is a physical and logical method for performance improvement of cluster systems. Efficient load balancing of cluster systems is the best logical method. Recently, the WLC (Weighted Least Connection) algorithm was used for load balancing of cluster systems. But, the algorithm also has load imbalance between servers because it uses an inaccurate load status of servers. In this paper, the author suggested a more efficient load balancing algorithm based on various load states of servers in real time. The author implemented a prototype and tested its performance. The test result shows that the load imbalance phenomenon is improved greatly and response time is also improved compared with the WLC algorithm.