Individual creativity is a critically important factor for organizational innovation, competitiveness, and long-term success. Creativity researchers have demonstrated that individual characteristics (e.g., creative personality, openness) and organizational environmental characteristics (e.g., work environment, leadership) are related to individual creativity. In particular, one of the important independent variables affecting individual creativity is job characteristics. According to Hackman and Oldham (1980), five job characteristics exist: job autonomy, task identity, task significance, skill variety, and job feedback. This study examined the effects of these five job characteristics on individual creativity and tested whether employees' proactive behavior significantly mediates the relationship between job characteristics and individual creativity. Data were collected through surveys administered to employees in R&D departments across 14 companies, yielding 154 matched pairs (supervisor-subordinate). Employees reported on job characteristics and proactive behavior, while supervisors evaluated employees' individual creativity. To test the research hypotheses, structural equation modeling was tested using AMOS 4.0. The analysis results revealed that the five job characteristics positively influenced individual creativity. Furthermore, these job characteristics positively influenced employees' proactive behavior, and proactive behavior positively influenced individual creativity. Finally, employees' proactive behavior was found to fully mediate the relationship between job characteristics and individual creativity. This study has several significant theoretical implications. First, this study contributes to creativity research by examining the relationships between various job characteristics and individual creativity. Such an approach has been very rare in creativity research. Second, this study uncovered the mediating process through which job characteristics influence individual creativity. Lastly, the findings of this study provide practical implications suggesting that individual creativity can be enhanced through job design and that organizations need to provide a work environment that promotes employees' proactive behavior in order to enhance individual creativity.