Incumbents
- Emperor: Hirohito (Emperor Shōwa)
- Prime Minister: Yasuhiro Nakasone (L–Gunma, 2nd term)
- Chief Cabinet Secretary: Takao Fujinami (L–Mie) until December 28, Masaharu Gotōda (L–Tokushima)
- Chief Justice of the Supreme Court: Jirō Terata until November 3, Kōichi Yaguchi from November 5
- President of the House of Representatives: Kenji Fukunaga (L–Saitama) until January 24, Michita Sakata (L–Kumamoto)
- President of the House of Councillors: Mutsuo Kimura (L–Okayama)
- Diet sessions: 102nd (regular session opened in December 1984, to June 25), 103rd (extraordinary, October 14 to December 21), 104th (regular, December 24 to 1986, May 22)
Read more about this topic: 1985 In Japan