This paper examines how Japanese physicists came to realize the importance of engaging in public relations during the early 20th century, focusing on their statements in the popular media. In the first half of the 20th century, Japanese physics had made much progress. Outstanding scholars such as Hideki Yukawa（湯川秀樹）, the first Nobel prize laureate in Japan were active in the 1930s, when Japanese saw the construction of the largest cyclotron outside the U.S. This progress was covered by newspapers and popular magazines whose articles envisioned a rosy future through scientific progress. Science articles in the mass media demanded scientists’ remarks and scientists required to respond. Two main figures will be discussed and contrasted. The first is Hantaro Nagaoka（長岡半太郎）, the most eminent and significant physicist among the first generation that had been trained in Japan. The second is Yoshio Nishina（仁科芳雄）, who was regarded as the founding father of modern physics in Japan. Nagaoka was born in 1865. After graduating from (Tokyo) Imperial University, he studied under Ludwig Boltzmann in Germany for 3 years. He made efforts to help scientific education put down roots in Japan. He started to appear in the public media in 1905, shortly after Japanese victory in the Russo-Japanese war. He also wrote a popular science book in 1906. Nagaoka’s public statements at this time however did not catch much popular attention. Nishina was born in 1890. He studied more than 5 years at Niels Bohr’s laboratory in Copenhagen. After returning to Tokyo, he founded a laboratory which was modeled after that in Copenhagen. He constructed two cyclotrons in the late 1930s. During WWII, he became a leader of the Japanese nuclear weapons research project. In the meantime, Nishina started to appeal to the public: he opened his laboratory and performed public experiments. The public were enchanted by his performances. This paper will argue that Japanese physicists gradually learned how to appeal to the public. When Japanese physicists became aware of the importance of public relations, Japan was in the process of militarization, the public sphere was formulated. A connection between physics and the war was made in the public sphere. Different strategies of public relations reveal changes in the public status of physics and science in early 20th Japan.