 Raymond BurrSteve Martin | Steve Martin |
 Takashi ShimuraDr. Yamane | Dr. Yamane |
 Momoko KôchiEmiko Yamane | Emiko Yamane |
 Akira TakaradaOgata | Ogata |
 Akihiko HirataDr. Serizawa | Dr. Serizawa |
 Sachio SakaiHagiwara | Hagiwara |
 Fuyuki MurakamiDr. Tabata | Dr. Tabata |
 Ren YamamotoSeiji | Seiji |
| TToyoaki SuzukiShinkichi | Shinkichi |
 Tadashi OkabeDr. Tabata's Assistant | Dr. Tabata's Assistant |
 Toranosuke OgawaPresident of Company | President of Company |
 Frank IwanagaSecurity Officer Tomo Iwanaga | Security Officer Tomo Iwanaga |
 Sammee TongDr. Yamane / Dr. Tabata / misc. characters (voices) (uncredited) | Dr. Yamane / Dr. Tabata / misc. characters (voices) (uncredited) |
 James HongOgata / Dr. Serizawa / Hagiwara / misc. characters (voices) (uncredited) | Ogata / Dr. Serizawa / Hagiwara / misc. characters (voices) (uncredited) |
| AAmy IwanabeEmiko Yamane (voice) (uncredited) | Emiko Yamane (voice) (uncredited) |
 Mikel ConradGeorge Lawrence (uncredited) | George Lawrence (uncredited) |
 Paul FreesUnidentified Character (voice) (uncredited) | Unidentified Character (voice) (uncredited) |
 Hiroshi HayashiChairman of Diet Committee (uncredited) | Chairman of Diet Committee (uncredited) |
| RRen ImaizumiRadio Operator (uncredited) | Radio Operator (uncredited) |
 Kokuten KōdōThe Old Fisherman (uncredited) | The Old Fisherman (uncredited) |
| TTakeo OikawaChief of Emergency Headquarters (uncredited) | Chief of Emergency Headquarters (uncredited) |
 Tsuruko ManoThe Boy's Mother (uncredited) | The Boy's Mother (uncredited) |
 Kenji SaharaMan on Boat (uncredited) | Man on Boat (uncredited) |
 Kin SugaiOzawa-san (uncredited) | Ozawa-san (uncredited) |
 Lee MillerMan in Line at Airport (uncredited) | Man in Line at Airport (uncredited) |
 Haruo NakajimaGodzilla (uncredited) | Godzilla (uncredited) |
 Katsumi TezukaGodzilla (uncredited) | Godzilla (uncredited) |
| RRyosaku TakasugiGodzilla (uncredited) | Godzilla (uncredited) |
