Mamehara Issei (豆原一成) is a Japanese artist under Lapone Entertainment. He is a member of the Japanese pop group JO1.
- Name: Mamehara Issei (豆原一成)
- Birthdate: May 30, 2002
- Birthplace: Okayama, Japan
- Blood Type: O
- Height: 173cm
- Weight: 69kg
- Hobbies: Dancing, singing, looking at clothes on Mercari, making TikToks
- Specialties: 90's Hip-Hop, baseball, swimming, doing Kamen Rider impressions
- He placed 1st on Produce 101 Japan.
- His official color is Red.
- He has an older sister.
- He was a dance instructor before joining Produce 101 Japan.