Events in the year 2010 in Japan.

• Emperor – Akihito^[1]
• Prime Minister – Yukio Hatoyama (Democratic Party–Hokkaidō) until June 8, Naoto Kan (Democratic Party–Tokyo)
• Chief Cabinet Secretary: Hirofumi Hirano (D–Ōsaka) until January 7, Yoshito Sengoku (D–Tokushima)
• Chief Justice of the Supreme Court: Hironobu Takesaki
• President of the House of Representatives: Takahiro Yokomichi (D–Hokkaidō)
• President of the House of Councillors: Satsuki Eda (D–Okayama) until July 25, Takeo Nishioka (D–proportional) from July 30
• Diet sessions: 174th (regular, January 18 to June 16), 175th (extraordinary, July 30 to August 6), 176th (extraordinary, October 1 to December 3)

• January 1 – The towns of Nijō and Shima merged with the city of Maebaru to form the city of Itoshima.
• January 3 – Japan doubles a state-sponsored credit line to troubled airline Japan Airlines to ¥200bn (US$2.2bn).^[2][3]
• January 6 – Japanese Finance Minister Hirohisa Fujii resigns at the age of 77 due to ill health.^[4]
• January 12 – A gunman kills three people at a bar in Habikino, Japan, before turning the gun on himself.
• January 19 – Japanese air carrier Japan Airlines files for bankruptcy protection.^[5]
• February 1 – The town of Kozakai merged into the city of Toyokawa.
• May 20 – JAXA successfully launched the venus probe Akatsuki (formerly "Planet-C").^[6]
• April 17 – Snowfall in central Tokyo matches a record set in April 1967.^[7]
• April 25 – Nearly 100,000 people rally in Okinawa, Japan, demanding the removal of an American base from the island.
• June – September – According to Japanese government and Japan Meteorological Agency official confirmed report massive heat wave and extreme high temperature hit around Japan, total 1,731 person were human fatalities relative heat stroke.^{[citation needed]}
• June 2 – Prime minister Yukio Hatoyama announced that he would be resigning as Prime Minister.
• June 4 – Naoto Kan is elected as the leader of the Democratic Party and therefore as Prime Minister of Japan, defeating Shinji Tarutoko.
• June 13 – The first Japanese asteroid probe, Hayabusa returned to Earth, after having landed on 25143 Itokawa in an effort to collect samples.^[8]
• July 11 – House of Councillors election
• August 9 – Japan marks the 65th anniversary of the 1945 atomic bombing of Nagasaki.
• September 11 – Jordan signs a nuclear co-operation treaty with Japan to build a nuclear power plant within 10 years.^{[citation needed]}
• September 14 – Naoto Kan is reelected as the leader of the Democratic Party of Japan and therefore as Prime Minister of Japan, defeating powerbroker Ichiro Ozawa.^[9][10]
• October 20 - Devastating floods and landslide in Amami Island, 3 people die.^[11]
• December 7 – The spacecraft Akatsuki reaches Venus but fails to enter orbit around the planet.

• Ei-ichi Negishi, Akira Suzuki: 2010 Nobel Prize in Chemistry winners.

• 2010 in Japanese music
• 2010 in Japanese television
• List of Japanese films of 2010