Shounen Himitsu Club

 (少年秘密倶楽部) is a Japanese 2.5D idol group formed in summer 2022. The group is produced by former Fudanjuku member Sueyoshi Sakiko.

The group currently consists of six female members playing male characters.

Current Members

 * Toru (透; ) (Original member)
 * Aiichiro (愛一郎; ) (Original member)
 * Natsu (ナツ; ) (Original member)
 * Ayumu (あゆむ; ) (Original member)
 * Ouga (オウガ; ) (Joined August 6, 2023)
 * Tatsuki (タツキ; ) (Joined August 7, 2023)

Former Members

 * Hikaru (ヒカル; ) (Original Member; Graduated March 28, 2023)
 * Yami (ヤミ; ) (Original member; Graduated June 7, 2023)

History
2022=

2022
2023=
 * April 3 - Auditions for the group were opened.
 * June 14 - The preview video for the group was released and the date of their debut live was announced.
 * From July 3 to July 15 - The 2D and 2.5D visuals were revealed one by one.
 * From July 16 to August 4 - Lyric videos of their five songs were released on YouTube.
 * August 5 - Their debut live Aim The Freedom was held at SELENE b2.
 * August 17 - Fanclub was opened.
 * September 3 - They started to do voice-only streams on YouTube.
 * November 11 - New song Jiyuu no Kishu (自由の旗手) was performed for the first time.
 * December 4 - They announced that they would stream their show Shounen Himitsu Club no Secret Time (少年秘密倶楽部のシークレットタイム) via Openrec. The show had eight episodes.
 * December 7 - Natsu went on a hiatus until January 23, 2023 because of surgical removal of tonsils.
 * December 31 - The group opened auditions to find 2nd generation members.

2023

 * January 17 - They started to do 2D streams on YouTube.
 * February 10 - Their 6 months anniversary live was held at SELENE b2.
 * March 28 - Hikaru graduated.
 * April 1 - It was announced that once they get 150 people to participate their regular lives, they will open individual Twitter accounts for the members.
 * From April 27 to April 30 - they had a stage play called Shounen Himitsu Club -Rei- (少年秘密倶楽部-零-) at BOX in BOX Theater. The play told the group's backstory.
 * June 7 - Yami graduated.
 * August - New visuals and a new song Guren no Shiki (紅蓮の四季) were revealed. New members Ouga and Tatsuki joined.
 * October 6 - New song Soushisouai Risoukyou (相思相愛理想郷) was revealed after the members gained 3000 Twitter followers in total.

Unreleased Songs

 * 1) Senretsu no Resistance (戦烈のレジスタンス)
 * 2) Hangeki no Sign (反撃のSign)
 * 3) Chisakimono (小さきもの)
 * 4) Junjo Kyoshikyoku (純情狂詩曲)
 * 5) Hadaka no Ousama (ハダカノオウサマ)
 * 6) Uchuu de Ichiban no Kimi (宇宙でイチバンの君)
 * 7) Jiyuu no Kishu (自由の旗手)
 * 8) Guren no Shiki (紅蓮の四季)
 * 9) Soushisouai Risoukyou (相思相愛理想郷)

Trivia

 * The characters that the members are playing belong to a secret organization that is rebeling against the absurd world. They aim to bring courage to people with their rock music.
 * The members stream as Vtubers on the group's YouTube channel in addition to their idol activities.
 * The members cover a part of their faces with a mask when they post live videos or photos.