Companies with women on board deliver higher average returns on equity, lower net debt-to-equity, and better average growth (Catalyst, 2007). Women are keen on social responsibility, customer satisfaction, and corporate governance (International Labour Office, 2015). Socially conscious investors worldwide interested in ESG investment will invest in companies with women on board. Despite much evidence, women are still underrepresented in the workforce worldwide. It is remarkably seen in Japan. Japan lists 120th in the Global Gender Gap Report (World Economic Forum, 2021). In 2017, among MSCI Japan Investable Market Index top 500 constituents, only 5 companies had over 30% of women on boards, and 287 companies had no female board directors (MSCI ESG Research, 2018). It shows that Japan’s gender gap in business is significant. This study aims to reveal the key issues Japanese female employees face in different industries. The research interviewed ten Japanese female leaders working in Japan, asking about their experiences. Qualitative data analysis was attempted to understand what the interviewees experienced, how they felt, and what is needed to change the situation. The finding indicated that the critical factor hindering women’s advancement is people’s unconscious biases for many years. Changing the deep-rooted common sense and habits in society is not easy. However, some measures that can be taken were revealed. These measures found in the research should provide knowledge for the future study of organizational diversity.