The large size of the Japanese IT market makes it attractive to and important for foreign high technology companies. However, the Japanese market is very challenging, highly competitive, and difficult to penetrate for foreign small and medium-sized enterprises (SMEs). Most SMEs fail to penetrate into the Japanese market effectively by using modern IT-tools in the international subsidiary establishment process. No earlier in-depth empirical research exists on the IT-supported international subsidiary establishment process for this market. This study investigated and analyzed how a Finnish high technology SME implemented the ITsupported international subsidiary establishment process for the Japanese market. In this study, a case study method was used to execute the research. This study validated and refined a conceptual model of the ITsupported international subsidiary establishment process by using empirical data. The research findings revealed that by using various IT-tools high technology companies can improve their internationalization process, penetrate the Japanese market rapidly and effectively, and manage global information exchange. This study also demonstrates that the use of IT-tools in the international subsidiary establishment process includes some limitations and not all tasks can be performed using ITtools alone. The research findings in this study are useful for both practice and further research.