Shinjirō Koizumi

is a Japanese politician who has been the Minister of Defense since 2025. He was the Minister of Agriculture, Forestry and Fisheries for a few months in 2025. He was the Minister of the Environment from 2019 until 2021. He has also been a Member of the House of Representatives for the Liberal Democratic Party since 2009. He is the second son of former Prime Minister Junichirō Koizumi.

In January 2020, Koizumi received international news attention when he announced his plans to take two weeks of paternity leave when his first child was born.

LDP leadership elections
2024

In September 2024, Koizumi announced his candidacy for the Liberal Democratic leadership election to replace Prime Minister Fumio Kishida. He lost the election to former Defense Minister Shigeru Ishiba on 27 September 2024.

2025

After Prime Minister Ishiba resigned, Koizumi announced his second leadership candidacy in September 2025 for the 2025 leadership election. On 4 October, election day, former Economic Minister Sanae Takaichi came in first place during the first round of voting with 183 (31.07%) of the vote. Koizumi came in second with 164 (27.84%) of the vote, meaning that both Koizumi and Takaichi advanced to the run-off to elect the party leader. Takaichi would go on to defeat Koizumi in the run-off by a 54% to 46% margin.

Minister of Defense (since 2025)
On 21 October 2025, Koizumi was appointed as Minister of Defense by Prime Minister Sanae Takaichi.

References

Category:1981 births
Category:Living people
Category:Politicians from Kanagawa Prefecture
Category:Liberal Democratic Party (Japan) politicians
Category:Environment ministers of Japan
Category:Ministers of agriculture, forestry and fisheries of Japan
Category:Defense ministers of Japan