This research has seven factors such as top management leadership, belt system operation, implementation of systematic methods, adequate project performance measurement, customer focus performance, quality performance and business performance. Those are critical to correct implementation of Six Sigma. I set seven hypotheses which represented the relationships among the seven factors, gathered questionnaires and analyzed the data. Top management leadership affected positively the adequate project performance measurement and the belt system operation, The belt system operation affected the implementation of systematic methods positively and it also affected the adequate project performance measurement. It affected positively the customer focus performance, the quality performance and the business performance, respectively.