In the knowledge-based economy, technological knowledge (TK) is reckoned key subject of knowledge management. Despite growing recognition, it has long been considered an intractable task to develop precise measures of TK and, as a remedy, a number of R&D-related proxy indicators have been employed. Although voluminous previous research has examined the structure and process of technological innovation by using proxy indicators, the inquiry into the relationship among respective indicators has remained unexplored. In this research, we take three most frequent proxy indicators of TK, R&D human resources, R&D stock, and patents, and investigate the correlation among respective measures. In addition, the dynamic pattern of time lag between technological input and output is also analyzed.