This research analyzes empirically the structural relationship among intellectual capital components such as human capital, structural capital and relational capital, and organizational performance in public R&D organizations. The measurement indices were developed for intellectual capital and performance : they were 10 factors and 37 indicators for intellectual capital and 2 factors and 5 indicators for organizational performance. They were confirmed statistically reliable. From this survey research, using the structural equation model, it was found a cycling relationship among three components: human capital causes structural capital, structural capital causes relational capital, and relational capital causes human capital. And it was also found a causal relationship between intellectual capital and organizational performance : human capital→ structural capital→ relational capital→ organizational performance. In the analysis of relative importance on organizational performance, the variables such as customer`s satisfaction, brand value creation activities, research planning activities, intellectual competence, interdependence, etc. were confirmed as an important variables affecting.