GunMax Armor is is formed from the combination of BP-601 GunMax and his Gun Bike. He can then transform into the Max Cannon as a weapon for J-Decker or Fire J-Decker.

When having to combat dangerous threats, GunMax will combine with the Gun Bike to form GunMax Armor, without needing for Yuuta to order any sort of combination command. When combined, GunMax Armor boasts an overall higher performance and gaining flight abilities, although he could not fly for long periods. Similar to GunMax, GunMax Armor is also equipped with a revolver (albeit larger than GunMax's) and a shotgun. Lastly, GunMax Armor in his separated mode (GunMax sitting on Gun Bike) can transform into the powerful Max Cannon and combine with J-Decker's right side skirt armor, which will allow J-Decker to fire the powerful weapon.

GunMax first used this configuration when he is infiltrating the Hourglass trash processing factory. He was met with resistance from the robots that the AI stationed there built, which eventually overpowered and captured him. However, Yuuta saved GunMax Armor just as he was about to be thrown into the incinerator by rewiring his movement circuit, which allowed for the Brave robot to break free and regroup with the other Braves, as Yuuta shuts down the factory's AI.

In the following episode, GunMax Armor in his separated mode transformed into the Max Cannon and combined with J-Decker to destroy an enemy robot.