- Masaaki Daimon
- Keisuke Shimizu
- Kazuya Aoyama
- Masahiko Shimizu
- Reiko Tajima
- Saeko Kanagusuku
- Akihiko Hirata
- Professor Hideto Miyajima
- Hiromi Matsushita
- Ikuko Miyajima
- Hiroshi Koizumi
- Professor Wagura
- Masao Imafuku
- Tengan Kunigami, the Azumi Royal Family High Priest
- Bellbella Lin
- Nami Kunigami, the Azumi Royal Family Princess
- Shin Kishida
- Interpol Agent Nanbara
- Gorô Mutsumi
- Alien Supreme Leader Kuronuma
- Daigo Kusano
- Yanagawa, Alien Agent #1
- Takayasu Torii
- Interpol Agent Tamura
- Kenji Sahara
- Ship's Captain
- Yasuzô Ogawa
- Construction Foreman
- Takamitsu Watanabe
- Alien Henchman # 1
- Takanobu Tôya
- Alien Henchman # 2
- Kôji Ozaki
- Alien Henchman # 3
- Isao Zushi
- Godzilla
- Ise Mori
- Mechagodzlla
- Kinichi Kusumi
- Anguirus / King Shîsâ (as Momoru Kusumi)
- Hal Archer
- Nanbara / Masahiko Shimizu (voice)
- Akio Kusama
- Kaiyohaku construction site worker
- Michael A. Ross
- Kuronuma / Hotel desk clerk (voice)
- Michael Kaye
- Professor Hideto Miyajima / Interpol Agent Tamura / Ship's Captain / Henchman (voice) (uncredited)
- Matthew Oram
- Keisuke Shimizu / Radio Announcer (voice) (uncredited)