Yukimitsu Koshi is a Japanese voice actor known for his work in anime, video games, and adult-oriented content, the latter of which is where this credited name primarily appears. His legal or primary professional name is Norio Kobayashi. He was born on September 21, 1973, in Niigata Prefecture, Japan. He is a graduate of the Baobab Gakuen, the 11th term of what is now known as the Visual Space Actors' Training School. Kobayashi has been affiliated with the talent agency y-tail (formerly Yellow Tail) and was previously a member of Production Baobab.

His voice is described as calm, steady, and dignified, a quality that has led to his frequent casting in historical dramas and period pieces. One of his most prominent and recurring roles is Genzaburō Inoue in the long-running Hakuoki franchise of games and anime. Other notable anime and game roles include Heisuke Kagano in the Hanayaka Nari, Waga Ichizoku series, Keizaburō Uzuchi in the 2018 anime adaptation of Nil Admirari no Tenbin, and a large spectator in A Story Behind Two Idols. He also voiced Kitou Masami in the 2020 series Library Girlfriend and Gonzou in the 2013 series Snake God's Comfort Festival.

As Yukimitsu Koshi, he performed the role of Haree in the 2014 adult animated short Erotic Encounter of the Alien Kind. For work in adult games and anime, he consistently uses the alias Yukimitsu Koshi.