This paper aims to explore why Japanese companies competitiveness has decreased, and to clarify the true reasons for it and provide the way to recover. And the paper examines the decline of Japanese companies, comparing it to the progress of Chinese companies contrastingly. Depending on ‘2019 Fortune Global 500’, 129 Chinese companies were ranked in, and at last surpassed the U.S. 121 companies in the number. This paper concluded the reason of decreasing competitiveness which Japan encountered as the delay of digital transformation (DX) and the weakness of top management leadership. And, moreover, as the prescription to recover the decline of Japanese companies competitiveness, this paper recommended ‘ambidexterity management’ as the methods of conquering innovations dilemma. On one hand, the company ‘explores’ efficiency through conventional main businesses, but on the other hand, it ‘exploits’ innovation through new businesses. This is an ambidexterity management.