Born on April 29, 1932, in northeastern China (formerly Manchuria), Tanaka Terumi graduated from the Department of Physics at the Tokyo University of Science. He holds a Doctor of Engineering. In 1938, due to the death of his father, he moved to Nagasaki where his parents' older sisters lived. On August 9, 1945, while in his first year at Nagasaki Prefectural Junior High School, he was exposed to the atomic bomb at a distance of 3.2 kilometers from the epicenter. The lives of five family members of two aunts who were near the epicenter were taken instantly, and his maternal aunt was cremated in a field. Since 1972, he has been involved in the Hibakusha movement, serving as an officer of the Miyagi Prefecture A-bomb Victims Association and the Japan Confederation of A- and H-Bomb Sufferers Organizations (Nihon Hidankyo), and has been the Secretary-General of the Nihon Hidankyo Secretariat since June 2000. Since June 2017, he has been a Co-chair of the Nihon Hidankyo.
In December 2024, Tanaka delivered the Nobel Lecture at the Nobel Peace Prize award ceremony at the Oslo City Hall, on behalf of the 2024 laureate Nihon Hidankyo. Tanaka is a Co-chair of the Japan NGO Network for Nuclear Weapons Abolition and is President of the Japan Campaign to Abolish Nuclear Weapons.