is a Japanese racing driver. He finished runner-up in the 2022 F4 Japanese Championship. He was a member of the Honda Formula Dream Project.
In 2022 Mitsui made his single-seater racing debut by competing in the F4 Japanese Championship. He joined the Honda Formula Dream Project team alongside Syun Koide, and Kazuma Nishimura. He won the opening race of the season and he collected 2 more wins along with 8 more podiums to finish runner-up to teammate Koide. For 2023, Mitsui stayed in F4 to fight for the title alongside Yuto Nomura, and rookie Tosei Moriyama. Mitsui ended up finishing 3rd place in the standings to Runners Up Jin Nakamura, and the eventual champion Rikuto Kobayashi.
Mitsui would take up a role as the third driver for Team UpGarage in 2024. But Mitsui did not made a single race in that season.
Mitsui joined new team Delightworks Racing for his Super Formula Lights debut in 2025.
Mitsui also made his debut in Super Taikyu with Honda's M&K Racing in 2023. Mitsui then raced for Team Spoon in the ST-2 class in 2024, and one race appearance with Honda's HRC Team in ST-Q.
<sup>*</sup> Season still in progress.<br> â¡ Team standings
() (Races in bold indicate pole position) (Races in italics indicate fastest lap)
() (Races in bold indicate pole position; races in italics indicate fastest lap)
<sup>*</sup> Season still in progress. <sup>â </sup> did not involve in the round thus no points rewarded.
() (Races in bold indicate pole position) (Races in italics indicate fastest lap)
<sup>*</sup> Season still in progress.