Hiroshi Koizumi

Tsukioka

Setsuko Wakayama

Hidemi

Minoru Chiaki

Kobayashi (as Mindru Chiaki)

Takashi Shimura

Dr. Yamane

Masao Shimizu

Dr. Tadokoro

Seijirô Onda

Commander (as Serjiro Onda)

Sonosuke Sawamura

Shibeki

Yoshio Tsuchiya

Tajima

Mayuri Mokushô

Radio Operator

Yukio Kasama

Father (as Yokio Kasama)

Takeo Oikawa

Police Chief

Minosuke Yamada

Chief of Civil Defense (uncredited)

Ren Yamamoto

Ikeda (uncredited)

Shin Ōtomo

Convict Leader (uncredited)

Senkichi Ōmura

Convict (uncredited)

Haruo Nakajima

Gigantis (uncredited)

Katsumi Tezuka

Angurus (uncredited)

Shōichi Hirose

Convict (uncredited)

Keye Luke

Tsukioka / Policeman (voice) (uncredited)

Aya Oyama

Hidemi (voice) (uncredited)

Marvin Miller

Kobayashi / Dr. Yamane / Narrator (voice) (uncredited)

Paul Frees

Commander / Father / Convict (voice) (uncredited)

George Takei

Ikeda / Osaka SDF Dispatcher (voice) (uncredited)

Jane Chang

Radio Operator (voice) (uncredited)

James Yagi

Osaka SDF Captain (voice) (uncredited)