This study examined the role of flow experience in intellectual activity with an emphasis on the relationship between flow experience and creative behaviour in design using CAD. The study used confluence and psychometric approaches because of their unique abilities to depict a clear image of creative behaviour. A cross-sectional study questionnaire was used to collect data from 597 architecture design students. We found that both the characteristics of a design task and the interactivity of CAD positively predict the experience of flow. We also found that flow experiences partially mediate the relationship between the interactivity of CAD and creative behaviour in design. The theoretical and practical implications of these findings are also discussed.