This thesis explores the ethical and cultural aspects of IFRS adoption within Rakuten Group, Inc., one of Japan’s leading multinational corporations. It examines how the company’s approach to transparency, accountability, and ethical decision-making aligns with international accounting standards beyond mere regulatory compliance. The study highlights the influence of Japanese corporate culture on the interpretation and implementation of IFRS principles. Through qualitative analysis and case-based evidence, it reveals the multi-layered governance structure that shapes ethical accounting practices. The findings suggest that successful IFRS adoption in Japan requires not only technical alignment but also moral and cultural adaptation within corporate governance systems.