Whenever Information leak case had been happened, even though IT Infra systems were reinforced, those cases of kind were not decreased. It meant that the causes are not only the fault of IT, but also other things. So that the information leak cases should have been studied by the interdisciplinary way. There was a point of view for the Business Ethics which needed to be studied in the interdisciplinary way. Financial Information Leak Case of three representative Card Companies in Korea which is happened in 2014 was a case which was composed by many problems. These were bad circumstances, half-educated, lower salary, and the most of all, the C-Levels' ignorance of the law. By studying the CLD: Causal Loop Diagram of Business Ethics and those mentioned factors, few meanings were discovered. Firstly, this case was not a accident, but a predeterminate issue at all, because of the structural unethical corruption. Secondly, main reason of this case was not only criminals who leaked information, but also managers, especially CEO who didn't obey the law, forced that to employees. Thirdly, although those companies had moral guide and did CSR activities, it was not help to protect this information leak case. This study shows that the important thing was not the action for showing, but effective action to management for sustainability.