|First appearance||Kakusei! Mahhajasutisu|
|Used by||Masaru Mahha|
|Created by||Masaru Mahha|
|IOD system||Yes (left unit) (Episode 8 onwards)|
Mach Justice makes its first appearance in the series as a still model of a Crush Gear made from brown clay. It is described by Masaru as the original Gear that he had made.
Mach Justice is first used in a Gear Fight in episode 3 during Masaru's duel against Yuu in the Sanama exhibition game. In the midst of the battle between Garuda Phoenix and King Schwarz, Crush Kid throws the clay model Gear to Masaru who is struggling with the Gear Fight. The clay model transforms into a fully functional Crush Gear when it meets with Garuda Phoenix in mid-air, and Masaru names his new Gear "Mach Justice". Masaru continues his fight against Yuu with his new Gear until their battle is interrupted by a barrier activated by Sanama.
- Mach Justice is the only Crush Gear outside of ZET that has the left unit IOD.