This study investigated the effects and processes of R&D investments on technology exports in Korean manufacturing industries. We collected data for twelve years of thirteen Korean industries and used path analysis method to achieve the research objectives. The analysis results have following findings. First, they show R&D investments affect both new technology development and existing technology improvement positively. Second, new technology development, existing technology improvement and research productivity are found to affect technology export positively. Third, the effects of R&D investment on technology export are found to be positive through new technology development and existing technology improvement , but not so through productivity of R&D manpower. The contribution of this study is that it shows the process through which R&D investment affects technology export, in other words, the roles of mediating variables of new technology development, existing technology improvement and productivity of R&D manpower, while previous studies mainly focused on the direct relationship between the two constructs. Finally, it concludes that R&D investment affects technology export positively through technology differentiation(new technology development and existing technology improvement), but not through the productivity improvement of R&D manpower.