The purpose of this study is to verify the mediating role of self-efficacy as the influence of social workers’ ethical consciousness on job stress. To this end, a survey was conducted on 512 social workers, and data analysis using the SPSS 25.0 program was conducted. As for the mediating effect, a hierarchical regression analysis and Sobel-test by Baron and Kenny were conducted. As a result of the main analysis, first, basic ethics, client ethics, and institutional ethics of social workers increased self-efficacy. Second, the basic ethics and client ethics of social workers lowered job stress. Third, the basic ethics and client ethics of social workers lowered job stress through self-efficacy. As a result of the study, it suggests that it is important to practice to improve ethical consciousness and self-efficacy to prevent job stress of social workers.