Akihiko Hirata
as Dr. Shinzô Mafune
Ise Mori
as Mekagojira 2
Gorô Mutsumi
as Alien Leader Mugal
Kenji Sahara
as Army Commander Segawa
Ikio Sawamura
as Mafune's Silent Butler
Kazuo Suzuki
as Alien Henchman 1
Katsuriko Sasaki
as Biologist Akira Ichinose
Kotaro Tomita
as Professor Ôta
Tomoko Ai
as Katsura Mafune
Katsumasa Uchida
as Interpol Agent Jiro Murakoshi
Tomoe Mari
as Yuri Yamamoto
Shin Roppongi
as Yûichi Wakayama
Tadao Nakamaru
as Interpol Chief Tagawa
Yoshio Kirishina
as Alien Henchman 2
Toru Kawai
as Gojira
Katsumi Nimiamoto
as Chitanozaurusu
Masayoshi Kikuchi
as Alien Henchman 3
Shizuko Higashi
as Old Country Lady