Raymond Burr as Steve Martin

Toyoaki Suzuki as Shinkichi (as Tuyoaki Suzuki)

Frank Iwanaga as Security Officer Tomo Iwanaga (as Frank Iwaiga)

Akira Takarada as Ogata (as Akiro Takarata)

Akihiko Hirata as Dr. Serizawa

Sachio Sakai as Hagiwara

Takashi Shimura as Dr. Yamane

Momoko Kôchi as Emiko Yamane (as Momaku Kuchi)

Fuyuki Murakami as Dr. Tabata (uncredited)

Ren Yamamoto as Seiji (uncredited)

Mikel Conrad as George Lawrence (uncredited)

Toranosuke Ogawa as President of Company (uncredited)

Tadashi Okabe as Dr. Tabata's Assistant (uncredited)

Kokuten Kōdō as The Old Fisherman (uncredited)

Kenji Sahara as Man on Boat (uncredited)

Haruo Nakajima as Godzilla (uncredited)

Katsumi Tezuka as Godzilla (uncredited)

Raymond Royer as Unidentified Character (voice)

Michel François as Unidentified Character (voice)

Roland Ménard as Unidentified Character (voice)

Violette Jean as Unidentified Character (voice)

René Blancard as Unidentified Character (voice)

Maurice Favières as Unidentified Character (voice)

Dominique Rémy as Unidentified Character (voice)

Gérard Kérise as Unidentified Character (voice)

Louis Perdoux as Unidentified Character (voice)

Claude Dupuis as Unidentified Character (voice)

Eddy Rasimi as Unidentified Character (voice)