 | Hiroshi Koizumi als Shoichi Tsukioka |
 | Keye Luke als Shoichi Tsukioka (voice) |
 | Setsuko Wakayama als Hidemi Yamaji |
 | Aya Oyama als Hidemi Yamaji (voice) |
 | Minoru Chiaki als Kôji Kobayashi |
 | Marvin Miller als Koji Kobayashi / Narrator (voices) |
 | Masao Shimizu als Dr. Tadokoro |
 | Mayuri Mokushô als Yasuko Inouye, Koji's girl |
| Takeo Oikawa als Osaka Chief of Police |
 | Minosuke Yamada als Chief of Civil Defense |
 | Takashi Shimura als Doctor Yamane |
 | Sonosuke Sawamura als Foreman Shibeki |
 | Yoshio Tsuchiya als Member of Osaka's SDF Tajima |
| Yukio Kasama als President of Fishery Koehi Yamaji |
 | Paul Frees als Doctor Kyohei Yamane, Commander of Osaka's SDF Terasawa, President of Fishery Koehi Yamaji (voices) |
 | Ren Yamamoto als Commander of Landing Craft Ikeda |
 | George Takei als Commander of Landing Craft Ikeda (voice) |
 | Seijirô Onda als Commander of Osaka's SDF Terasawa |
 | Shin Ōtomo als Convict Leader |
 | Senkichi Ōmura als Convict |
 | Haruo Nakajima als Gigantis |
 | Katsumi Tezuka als Angurus |
 | Shōichi Hirose als Convict |
| Motoyoshi Oda | Director |
| Paul Schreibman | Producer |
| Hugo Grimaldi | Director |
| Masaru Satō | Original Music Composer |
| Masanobu Miyazaki | Sound Recordist |
| Rex Lipton | Music Editor |
| Seiichi Endo | Director of Photography |
| Masaki Ônuma | Lighting Technician |
| Edmund Goldman | Associate Producer |
| Tomoyuki Tanaka | Producer |
| Kazuo Baba | Production Manager |
| Takeo Kita | Production Design |
| Teruaki Abe | Production Design |
| Shigeru Kayama | Novel |
| Takeo Murata | Screenplay |
| Eiji Tsuburaya | Special Effects |
| Eiji Tsuburaya | Visual Effects |
| Sadao Iizuka | Visual Effects |
| Hugo Grimaldi | Editor |
| Paul Sawtell | Original Music Composer |
| Shigeaki Hidaka | Screenplay |
| Shigeru Kayama | Original Story |
| Hugo Grimaldi | Writer |
| Ib Melchior | Original Story |
| Ed Watson | Original Story |
