2005 Happenings
- 12 new albums
- 27 new singles
- 3 retirements
- 3 graduations
- 6 new groups
- 51 left groups
- 6 disbanded groups
- 7 joined groups
- 3 new leaders
- 1 new idols
- 2 ex-leaders
January 2005
- 1 Ootani Masae leaves H.P. All Stars
- 1 Ayaka leaves H.P. All Stars
- 1 Miuna leaves H.P. All Stars
- 1 Yaguchi Mari leaves H.P. All Stars
- 1 Abe Natsumi leaves H.P. All Stars
- 1 Iida Kaori leaves H.P. All Stars
- 1 Murata Megumi leaves H.P. All Stars
- 1 Shibata Ayumi leaves H.P. All Stars
- 1 Yasuda Kei leaves H.P. All Stars
- 1 Inaba Atsuko leaves H.P. All Stars
- 1 Konno Asami leaves H.P. All Stars
- 1 Takahashi Ai leaves H.P. All Stars
- 1 Tsuji Nozomi leaves H.P. All Stars
- 1 Saitou Hitomi leaves H.P. All Stars
- 1 Nakazawa Yuuko leaves H.P. All Stars
- 1 Hagiwara Mai leaves H.P. All Stars
- 1 Satoda Mai leaves H.P. All Stars
- 1 Okai Chisato leaves H.P. All Stars
- 1 Suzuki Airi leaves H.P. All Stars
- 1 Asami leaves H.P. All Stars
- 1 Sugaya Risako leaves H.P. All Stars
- 1 Nakajima Saki leaves H.P. All Stars
- 1 Kumai Yurina leaves H.P. All Stars
- 1 Miyoshi Erika leaves H.P. All Stars
- 1 Ishimura Maiha leaves H.P. All Stars
- 1 Natsuyaki Miyabi leaves H.P. All Stars
- 1 Sudou Maasa leaves H.P. All Stars
- 1 Ishikawa Rika leaves H.P. All Stars
- 1 Maeda Yuki leaves H.P. All Stars
- 1 Murakami Megumi leaves H.P. All Stars
- 1 Tokunaga Chinami leaves H.P. All Stars
- 1 Tsugunaga Momoko leaves H.P. All Stars
- 1 Yajima Maimi leaves H.P. All Stars
- 1 Shimizu Saki leaves H.P. All Stars
- 1 Fujimoto Miki leaves H.P. All Stars
- 1 Umeda Erika leaves H.P. All Stars
- 1 Tanaka Reina leaves H.P. All Stars
- 1 Michishige Sayumi leaves H.P. All Stars
- 1 Yoshizawa Hitomi leaves H.P. All Stars
- 1 Kamei Eri leaves H.P. All Stars
- 1 Niigaki Risa leaves H.P. All Stars
- 1 Gotou Maki leaves H.P. All Stars
- 1 Kago Ai leaves H.P. All Stars
- 1 Matsuura Aya leaves H.P. All Stars
- 1 Okada Yui leaves H.P. All Stars
- 1 Ogawa Makoto leaves H.P. All Stars
- 9 Heike Michiyo releases “Ran・RUN・Ran”
- 19 Morning Musume｡ releases “THE Manpower!!!”
- 30 Iida Kaori steps down as leader of Morning Musume｡
- 30 Iida Kaori leaves Morning Musume｡
- 31 Iida Kaori becomes a soloist
- 31 Yaguchi Mari becomes leader of Morning Musume｡
February 2005
- 1 H.P. All Stars disbands
- 9 Melon Kinenbi releases “Nikutai wa Shoujiki na EROS”
- 9 W releases “Koi no Fugue”
- 23 Gotou Maki releases “3rd Station”
- 23 Matsuura Aya releases “Zutto Suki de Ii Desu ka”
- 28 Heike Michiyo releases “Koimizuki”
March 2005
- 2 v-u-den releases “Kacchoii ze! JAPAN”
- 2 W releases “2nd W”
- 17 Ishii Rika releases “Kotoshima”
- 23 Mika releases “Mika”
- 24 Matsuura Aya releases “Matsuura Aya Best 1”
- 30 Berryz Koubou releases “Special Generation”
April 2005
- 14 Yaguchi Mari leaves Morning Musume｡
- 14 Yaguchi Mari steps down as leader of Morning Musume｡
- 15 Yoshizawa Hitomi becomes leader of Morning Musume｡
- 20 Abe Natsumi releases “Yume Naraba”
- 27 Morning Musume｡ releases “Oosaka Koi no Uta”
May 2005
- 7 Kusumi Koharu joins Morning Musume｡
- 7 Kusumi Koharu joins Hello! Project
- 7 Ishikawa Rika leaves Morning Musume｡
- 18 W releases “Ai no Imi wo Oshiete!”
- 25 v-u-den releases “Ajisai Ai Ai Monogatari”
June 2005
- 7 Elegies is formed
- 7 Sexy Otonajan is formed
- 7 Puripuri Pink is formed
- 8 Berryz Koubou releases “Nanchuu Koi wo Yatteruu YOU KNOW?”
- 11 Hello! Project・Kids disbands
- 11 Yajima Maimi becomes leader of ℃-ute
- 11 ℃-ute is formed
- 22 Sexy Otonajan , Puripuri Pink and Elegies release “Onna､ Kanashii､ Otona / Inshouha Renoir no You ni / Hitoshirezu Mune wo Kanaderu Yoru no Aki”
July 2005
- 6 Gotou Maki releases “Suppin to Namida。”
- 24 Puripuri Pink disbands
- 24 Sexy Otonajan disbands
- 24 Elegies disbands
- 27 Morning Musume｡ releases “Iroppoi Jirettai”
- 30 Ooyanagi Maho retires from show business
- 30 Ooyanagi Maho leaves Hello! Project
- 30 Ooyanagi Maho leaves HelloPro Egg
August 2005
- 3 Nochiura Natsumi disbands
- 3 Berryz Koubou releases “21ji Made no Cinderella”
- 10 v-u-den releases “Hitorijime”
- 31 Abe Natsumi releases “Koi no Hana”
September 2005
- 3 DEF. DIVA is formed
- 7 W releases “Miss Love Tantei”
- 21 Matsuura Aya releases “Ki ga Tsukeba Anata”
- 30 Kawashima Miyuki leaves HelloPro Egg
- 30 Kawashima Miyuki retires from show business
- 30 Kawashima Miyuki leaves Hello! Project
October 2005
- 1 Tomoiki・Ki wo Uetai is formed
- 2 Ishimura Maiha retires from show business
- 2 Ishimura Maiha leaves Hello! Project
- 5 v-u-den releases “Kurenai no Kisetsu”
- 19 DEF. DIVA releases “Suki Sugite Baka Mitai”
- 26 v-u-den releases “Suite Room Number 1”
November 2005
- 9 Morning Musume｡ releases “Chokkan 2〜Nogashita Sakana wa Ookii zo!〜”
- 16 Berryz Koubou releases “Dai ② Seichouki”
- 23 Berryz Koubou releases “Gag 100kai Bun Aishite Kudasai”
- 30 Abe Natsumi releases “Takaramono”
December 2005
- 7 Berryz Koubou releases “Special! Best Mini〜2.5 Maime no Kare〜”
- 9 Heike Michiyo releases “unaffected”
- 14 Gotou Maki releases “Gotou Maki Premium Best ①”
- 21 Iida Kaori releases “Plein d'Amour〜Ai ga Ippai〜”
- 21 Maeda Yuki , Morning Musume｡ , Melon Kinenbi , W , Berryz Koubou , Ecomoni｡ , v-u-den , Elegies , Puripuri Pink , Sexy Otonajan and DEF. DIVA release “Pucchi Best 6”
- 21 Gotou Maki releases “Maki Goto 2005 Special Edition for Hawaii”