Objectives: The researchers investigated the relationship among fun seeking, self-efficacy, interest in physical activity and actual physical activities of male college students, in orders to provide valuable information to professionals in health promotion. Methods: The participants were 316 male college students whose ages ranged from 18 to 30(M=22.53, SD=2.09). The questionnaires and psychological tests used in this research included the following: sub-scale of Korean Version of BAS/BIS Scale, The General Self-Efficacy Scale, International Physical Activity Questionnaires, & sub-scale of The Intrinsic Motivation Inventory for physical activity. Results: Results indicated that male students who had moderate level of fun seeking were more likely to engage in physical activities than those who showed low or high level of fun seeking. And students with the strong self-efficacy were more likely to do physical activity than with the weak self-efficacy, especially high level of physical activity. Male students who had greater interest in physical activity were more likely to engage in physical activities than those who were not interested in physical activity. A regression analysis revealed that interest in physical activity accounted for the most variance; it accounted for around 14.5% variance of actual physical activity with self-efficacy. The interaction effect of self-efficacy and interest in physical activity was significant for actual physical activity. Conclusion: This study reiterates the roles of self-efficacy and the interest in physical activity on physical activity, and found that non-linear relation of fun seeking to physical activity. These results may provide useful information for health practitioners.