Abstract: While the IT industry is technology-oriented, the IT service industry is service-oriented. The recent paradigm shifts from technology to service and efforts are needed to improve the efficiency of the IT service industry. There have been previous studies on this. In this study, we analyzed efficiency by differentiating from previous research. First, we expanded the research target companies. Secondly, we added input factors and output factors. We applied CCR and BCC Models of Data Envelopment Analysis (DEA) to analyze Technological Efficiency (TE) and Pure Technology Efficiency (PTE), analyzed the causes of inefficiency and suggest improvement directions. In addition, we applied the super efficiency model to determine the difference between efficient companies. It is expected that the efficiency of IT service companies will be improved by using the results of this study.