In order to manage technology transfer properly, it is important to judge whether the technology transfer is successful or not, and to find out the reason of the conclusion. The study aims to find out the relationship between successfulness of technology transfer and reasons or basis of the conclusion. Empirical investigation was carried out for Korean small and medium size firm in machinery and material field with statistical analysis on questionnaire and intensive interview. Result of the analysis is identified and compared with the other. It is shown that Korean firms feel their technology transfer is successful when it meet functional objectives and to get enough knowledge to further utilization from external source. Realization of benefit do not affect much the successfulness of technology transfer even though it is final objectives of technology transfer.