- Name: Ono Mizuho (小野瑞歩)
- Birthdate: September 29, 2000
- Birthplace: Tokyo, Japan
- Blood Type: O
- Height: 159cm
- Hobbies: Watching Hello! Project videos, dancing, listening to music, singing
- Specialties: Dance, playing the flute, making funny faces
- Favorite Food: Annin tofu, soybean flour twists
- Favorite Color: Pink, emerald green
- Looks Up To: Sato Masaki
- Hello! Project groups:
Ono Mizuho was first introduced as a member of Hello! Pro Kenshuusei through an announcement on the official Hello! Project website on April 27, 2015. The next year on August 13, 2016 she was revealed to be one of three new members of Tsubaki Factory, through a surprise announcement given at a fan club event for the group.
- [2020.09.29] MIZUH◎
- TV Programs
- [2016–2019] The Girls Live
- [2019–] AI・DOL PROJECT
-  Hello Pro! TOKYO Sanpo Season2 (ハロプロ！TOKYO散歩 Season2)
-  Ikuze! Tsubaki Factory (行くぜ!つばきファクトリー)
- [2016–] Hello! Station (ハロ！ステ)
-  Hello Pro no Oshigoto Challenge! (ハロプロのお仕事チャレンジ!)
-  Hello Pro Kouhaku Taiko THE☆BATTLE 2019 (ハロプロ紅白対抗 ザ☆バトル2019)
-  Hello Pro no Oshigoto Challenge! 2 (ハロプロのお仕事チャレンジ!2)
-  Hello Pro no Oshigoto Challenge! 3 e no Michi ~Kinkyuu Kikaku Kaigi~ (ハロプロのお仕事チャレンジ！3への道 ~緊急企画会議~)
-  Hello! Project presents..."Premiere seat"
-  Hello Pro no Collabo NIGHT! (ハロプロのコラボNIGHT!)
-  Nega Poji Poji (ネガポジポジ)
-  Harukanaru Toki no Naka de 6 Gaiden ~Tasogare no Kamen~ (遙かなる時空の中で６ 外伝 ~黄昏ノ仮面~)
- [2017–] Hello! SATOYAMA&SATOUMI Club
- Was part of News Entertainment School prior to joining Hello Pro Kenshuusei.
- Her favorite sport is dance.
- Her motto is "Don't forget your first resolution".
- Her favorite Hello! Project song is "Happy Daisakusen" by Morning Musume.
- Thinks her strength is her ability to turn things around and make them positive.
- Believes her weakness is being bad at waking up in the morning.
- Considers her charm points to be her big ears and her soft earlobes.
- Her dream is to debut in a cute and cool group in Hello! Project.
- Her favorite music genre is J-Pop.