In this paper, we describe the history and background of the Code of Ethics of the Institute of Electronics, Information and Communication Engineers（IEICE), which is the largest society for electronics, information and communication engineers in Japan. The IEICE members who established and revised this code did so after examining what a code of ethics should be and considering the social, technological, and ideological aspects of the institute's goals and operations. In this work, the history of the Code of Ethics of the IEICE is divided into three periods focuing on the development of the character of the ethical code and its relationship to the milieux of the institute:the foundation period when the code reflected the ethics of electronic networks;the 2011 revision period, when the code was made to reflect engineering ethics instead;and the 2023 re-revision period when ethics for an age of diversity and communication among various actors were added to the code.