"CEO's Leadership, Mediated By The Operating System And Line Managers’ Involvement Effect In The "GDM In HRM " -Business Case In US, Korean And Japanese Firms " Yukiko Nakagawa, Rikkyo University, Japan,2-21-16,Mita,Minato-ku,Tokyo,Japan Email Address: yukiko.nakagawa@rikkyo.ac.jp Abstract This paper compares and verifies the causes of the "low Gender Diversity Management (we call, GDM) in Human Resources Management (HRM) " phenomenon in Japanese companies, by selecting the Japanese Company A, the U.S. company GE, and the South Korean company Samsung Electronics (controlling for industry type, scale, and time since founding), and by conducting intensive interviews with HR directors. Intensive interviews made clear what sort of problems are occurring within the organization at the Japanese Company A, and also revealed that the problems of asymmetrical of information and misaligned interests among the CEO, senior management, and managers are also having a considerable effect. Next, the ways by which the same problems are being resolved within the organization at GE and Samsung were made clear. Opportunistic behavior by the mid-level managers toward senior management can be considered to exist in all sorts of organizations. Due to the fact that CEO, senior management and line managers within a firm have different perceptions of GDM. However, we asked in the intensive interviews whether strategic operating system to suppress this opportunistic behavior in multiple perspectives have been introduced into organizational management and whether these are functioning. Accordingly, it becomes clear that the problem of misaligned interests and asymmetrical of information is occurring among managers who are aiming for overall optimization and sustained growth. Moreover, as the company's performance appraisal system places weight on the achievement of short-term benefits for managers' own divisions, signs of retaining talented human resources within managers' own divisions are apparent. Behind this lies site-driven individual optimization organizational management and it can be inferred that monitoring functions for overall optimization and incentive system functions are not well handled by