| Katsuji Mori | Gô Mifune (1967-1968) |
| Peter Fernandez | Speed Racer/James Racer/Racer X/Additional Voices |
| Jack Curtis | Pops Racer/Lionel Racer/Inspector Detector/Announcer/Additional Voices |
| Jack Grimes | Sparky/Wilson Sparkolemew/Chimchim/Additional Voices |
| Corinne Orr | Trixie/Sprytle/Mom Racer/Additional Voices |
| Kinya Aikawa | Masked Racer/Ken'ichi Mifune (1967-1968) |
| Kei Tomiyama | Sabu (1967-1968) |
| Kenji Utsumi | Inspector Rokugô (1967-1968) |
| Teiji Ômiya | Daisuke Mifune (1967-1968) |
| Hiroshi Ôtake | Sanpei (1967-1968) |
| Junko Hori | Kurio Mifune (1967-1968) |
| Ryôko Kinomiya | Aya Mifune (1967-1968) |
| Yoshiko Matsuo | Michi 'Mittchi' Shimura #1 (1967) |
| Michiko Nomura | Michi 'Mittchi' Shimura #2 (1967-1968) |
