The purpose of this study was to verify whether there are any differences in the level of physical self-efficacy, depression and stress of meddle-aged men according to the stage of exercise change. As for the study objects, men at the ages between 40 and 50, residing in Seoul and mostly having temporary jobs, office jobs and professional jobs, were surveyed with the questionnaire prepared, and 299 copies of the questionnaire in total were collected and used for the final analysis. SPSS 12.0 was used for the processing of the data, while the results were deduced by using exploratory analysis, reliability analysis, 1-way ANOVA and correlation analysis. The study results were as follows: Firstly, their Physical self-efficacy showed significant differences according to the stage of exercise change of the study objects, and as a result of the post-hoc analysis, it was found that as the stage became higher, their physical self-efficacy became higher as well. Secondly, the level of depression showed significant differences according to the stage of exercise change of the study objects, and as a result of the post-hoc analysis, it was found that as the stage generally became higher, their depression showed lower levels. Thirdly, their stress showed significant differences according to the stage of exercise change of the study objects, and as a result of the post-hoc analysis, it was found that the preparation stage had a lower level of stress than the maintenance stage while the before-plan stage had a lower level of stress than the before-plan stage and the maintenance stage. Fourthly, it was found that as the stage of exercise change became higher, their stress tended to decrease while their self-efficacy tended to increase.