This study aims to verify the disparity in the relationship between external ethics(CSR activities) and internal ethics(earnings management) of a firm, depending on the KOSPI attributes and CEOs’ contingency factors. The external ethics is an ethical activity that can easily be observed from the outside, and the reflection of internal ethics, which is the actual level of ethics. However, some believe that external ethics is simply a part of external image management with no relations to internal ethics. Conflicting perspectives co-exist since firms’ CSR activities are different depending on the driving force behind ethical activities. If a firm has a high level of motive for ethical activities, then CSR activities will actually reflect its level of ethics, and external and internal ethics will match. However, if the motivation behind ethical activities is low, then CSR activities will simply become the tool of external image making, and it becomes unrelated to or conflicted with internal ethics. In such a way, the driver behind ethical activities, which affects the relevance of firms’ ethics, is different depending on KOSPI attributes and CEOs’ contingency factors. Therefore, this study aimed to verify the difference in the relevance of internal and external corporate ethics, depending on KOSPI attributes and CEO’s contingency factors. Main findings of the study are as follows: It was shown that CSR activities reduce earnings management. This means that internal ethics become superior as the level of corporate external ethics becomes higher. Also, it was revealed that CSR activities of KOSPI 200 corporations and CEOs with higher education or owner CEOs reduce the earning management further. On the other hand, CSR activities of initial appointed CEOs or CEOs with fraud experiences increase earnings management. In other words, there are differences in corporate external ethics" influence on internal ethics, depending on KOSPI attributes and CEOs" contingency factors. On the other hand, corporate external ethics actually reflecting the level of ethics could mean that internal ethics could affect external ethics, and the need for the analyses of actual proof was suggested. According to the analysis, CSR activities were reduced as the earnings management increased, and the effect was bigger for CEOs with higher education or owner CEOs. However, earnings management for the initial appointed CEOs or CEOs with fraud experiences increased CSR activities. This means that the effect of firms’ internal ethics on external ethics is different depending on CEOs" contingency factors. In particular, since initial appointed CEOs or CEOs with fraud experiences utilize CSR activities as the tool for external image making it is being implied that information users should recognize this fact and accommodate information differently.