- Kenji Sahara
- Shigeru Kawamura, colliery engineer
- Yumi Shirakawa
- Kiyo, Shigeru's lover
- Akihiko Hirata
- Professor Kyuichiro Kashiwagi (biology)
- Akio Kobori
- Police Chief Nishimura
- Yasuko Nakada
- Female Honeymooner
- Minosuke Yamada
- Colliery Chief Osaki
- Yoshifumi Tajima
- Izeki, reporter of Seibu Nippou
- Kiyoharu Onaka
- Male Honeymooner, Sunagawa's friend
- Hiroshi Akitsu
- Reporter
- Ichirô Chiba
- Chief of police station
- Mike Danning
- American Soldier Typing
- Tsurue Ichimanji
- Haru, Kiyo's neighbor
- Saburô Iketani
- News Reader
- Saburô Kadowaki
- Sunagawa's colleague
- Yoshio Katsube
- Correspondent
- Tateo Kawasaki
- Tsunesan, miner
- Kanta Kisaragi
- Suteyan, miner
- Eisaburo Komatsu
- Air Self-Defense Force Member
- Takuzô Kumagai
- Policeman Tashiro
- Saeko Kuroiwa
- Nurse
- Akio Kusama
- Suda
- Tsuruko Mano
- Osumi, Kiyo's neighbor
- Mitsuo Matsumoto
- Professor Isokawa
- Hideo Mihara
- Commander of JASDF
- Kiyomi Mizunoya
- Otami, Yoshizo's wife
- Jun'ichirô Mukai
- Military officer
- Toshiko Nakano
- Kiyo's neighbor
- Rinsaku Ogata
- Goro, miner, Kiyo's older brother
- Seiji Onaka
- Nakagawa
- Keiji Sakakida
- Tahei, miner
- Yasuhiro Shigenobu
- Sabu, miner
- Junnosuke Suda
- Coroner
- Shigemi Sunagawa
- F-86F pilot
- Jirô Suzukawa
- Yoshizo, miner
- Masaaki Tachibana
- Policeman
- Bontarô Taira
- Laborer
- Kiyoshi Takagi
- Dr.Minakami (colliery)
- Kamayuki Tsubono
- Policeman of the crime laboratory
- Mitsuo Tsuda
- Air Self Defense Force Staff Officer Takeuchi
- Hideo Unagami
- Miner
- Akira Yamada
- Radio operator on jeep
- Paul Frees
- Police Chief Nishimura
- Art Gilmore
- Narrator
- Shôichi Hirose
- F-86F pilot
- Ren Imaizumi
- Engineer Sunagawa (seismologist)
- Keiichirô Katsumoto
- Employee of the coal mine
- Keye Luke
- Shigeru
- Fuyuki Murakami
- Professor Minami (science)
- Haruo Nakajima
- Radon (Kaiju)
- Ichirô Nakatani
- Senkichi, miner, killed by Meganuron
- Yutaka Oka
- Kitahara, F-86F pilot
- Tadashi Okabe
- Journalist
- George Takei
- Professor Kashiwagi
- Katsumi Tezuka
- Hotel manager
- Yasuhisa Tsutsumi
- Imamura, F-86F pilot
- Kôji Uno
- Reporter
- James Yagi
- Voice
- Ren Yamamoto
- Soldier in Jeep
