As shown in the video, the band is Wet Floor, whose bass player is Ikuo Shibutani. This is confirmed by IMDB.
Composed by Tôru Minegishi
Performed by Wet Floor ( Hiroaki Takeuchi & Sachiko Watabe (vocals), Akitoshi Kuroda (guitar), Ikuo Shibutani (bass), Kei Yamazaki (drums) )
Recorded by Takashi Koiwa
My understanding of your question is that you are looking for the name of the cellist that appears in this video from 1'21" to 1'52" under the name ω-3.
This is 徳澤青弦 (Seigen Tokuzawa), a Japanese cellist. More on Wikipedia, Discogs and MusicBrainz.