Michael Keith

Eric Carter

Harry Holcombe

Dr. Arnold Johnson

James Yagi

Yutaka Omura

高島忠夫

Osamu Sakurai

佐原健二

Kazuo Fujita (as Keji Sahaka)

有島一郎

Mr. Tako (as Ichiro Arishima)

George Takei

Osamu Sakurai (voice) (uncredited)

Les Tremayne

Mr. Tako / Dr. Shigesawa / Dr. Akira Makino / General Masami Shinzo / Commander Roberts / Narrator (voice) (uncredited)

Byron Morrow

Newscaster (uncredited)