Steve Martin
Dr. Yamane
Emiko Yamane
Ogata
Dr. Serizawa
Hagiwara
Dr. Tabata
Seiji
Shinkichi
Dr. Tabata's Assistant
President of Company
Security Officer Tomo Iwanaga
Dr. Yamane / Dr. Tabata (voice) (uncredited)
Ogata / Dr. Serizawa / Hagiwara (voice) (uncredited)
George Lawrence (uncredited)
Unidentified Character (voice) (uncredited)
Chairman of Diet Committee (uncredited)
Radio Operator (uncredited)
The Old Fisherman (uncredited)
Chief of Emergency Headquarters (uncredited)
The Boy's Mother (uncredited)
Man on Boat (uncredited)
Ozawa-san (uncredited)
Man in Line at Airport (uncredited)
Godzilla (uncredited)