The purpose of this study was to predict the relationship between physical self-concept and exercise adherence based on the stage of exercise behavior change among adults participating in weight training, and identify the physical self-concept factors that affect exercise adherence. To achieve this goal, a survey was conducted using the exercise behavior change questionnaire, physical self-concept questionnaire, and exercise adherence questionnaire on 300 adults over the age of 20 residing in Gwangju. After excluding 44 questionnaires with incomplete responses, a total of 256 questionnaires were used for analysis. Data analysis was conducted using SPSS Ver. 25.0. statistical package program such as frequency analysis, exploratory factor analysis, Cronbach's α, independent t-test, One-Way ANOVA, Sheffe, and multiple regression analysis were used to analyze the data.In this study, we first analyzed the differences in physical self-concept and exercise adherence according to individual characteristics (gender, age, and exercise behavior change stage) in weight training participants, with a hypothesis to investigate the effects of exercise behavior change stages on physical self-concept and exercise adherence. Second, we analyzed the causal relationship between physical self-concept and exercise adherence in weight training participants. The results can be summarized as follows: First, the analysis of the differences in physical self-concept and exercise adherence according to the personal characteristics of weight training participants, statistically significant differences were found in the sub-factors of physical self-concept, including sports competence, health, physical activity, flexibility, endurance, and muscular strength, among which sports competence, body fat/thinness, health, physical activity, endurance, and muscular strength were higher in male participants, while appearance, self-esteem, and flexibility were higher in female participants. Second, statistically significant differences in exercise adherence were found in the sub-factors of tendency and reinforcement according to gender, and both tendency and reinforcement were higher in male participants. Third, the analysis of the differences in physical self-concept according to age showed that the sub-factors of physical self-concept, including sports competence, body fat/thinness, appearance, physical activity, flexibility, endurance, and muscular strength, were higher in the 20-23 age group, while health was higher in the 24-26 age group, and self-esteem was higher in the 27-29 age group, on average.Fourth, the analysis of the differences in exercise adherence according to age showed that both tendency and reinforcement were higher in the 20-23 age group, on average. In addition, Sheffe showed significant differences in both tendency and reinforcement between the 20-23, 24-26, and 27-29 age groups.Fifth, the analysis of the difference in physical self-concept according to the stages of exercise behavior change showed that all sub-factors of physical self-concept, including sports competence, body fat/thinness, appearance, health, self-respect, physical activity, flexibility, endurance, and muscle strength, were higher in the "maintenance stage" group, on average. Sixth, the analysis of the difference in exercise adherence according to the stages of exercise behavior change showed that both the tendency and reinforcement, which are sub-factors of exercise adherence, were higher on average in the "maintenance stage" group, on average. And Sheffe showed that there were significant differences between the "preparation stage," "action stage," and "maintenance stage" groups.Seventh, the analysis of the impact of physical self-concept on the tendency, a sub-factor of exercise adherence, showed that sports competence, appearance, physical activity, and muscle strength had a positive (+) impact, while body fat/thinness and self-respect had a negative (-) impact.Eighth, the analysis of the impact of physical self-concept on reinforcement, a sub-factor of exercise continuation, showed that sports competence, health, and physical activity had a positive (+) impact, while self-respect had a negative (-) impact.