Tsugumi Ōba (Profile in Japanese: 大場 つぐみ), born in Tokyo, Japan, is a writer best known for the manga Death Note. His/her real identity is a closely guarded secret. As stated by the profile placed at the beginning of each Death Note manga, Ōba collects teacups and develops manga plots while holding his knees on a chair, similar to a habit of L, one of the main characters of the series.

There is speculation that Tsugumi Ōba is a pen name and that he is really Hiroshi Gamō. Pointing out that in Bakuman the main character's uncle was a one-hit wonder manga artist who worked on a gag super hero manga, very similar to Gamō and Tottemo! Luckyman in all aspects. Also that the storyboards drawn by Ōba greatly resemble Tottemo! Luckyman in style.