PURPOSE: To simplify the structure of an auxiliary brake by providing a supporting bar on a base plate for connecting an axle to a leaf spring, providing a lever where the supporting bar is the fulcrum, and pulling the lever to push the brake pad against the brake disk.

CONSTITUTION: A brake disk 3 is provided opposite to the inner side surface of an axle 2, and a supporting bar 6 is provided on the base plate of a base plate 5 for connecting the axle 1 to a leaf spring. A lever 7 where the supporting bar 6 is the fulcrum is provided, and a brake pad 10 is connected to one end of the lever 7, while a return spring 11 and a brake wire 12 are connected to the other end. When the brake pad 13 is pulled, the brake wire 12 is interlocked to overcome the return spring 11, and the lever 7 is moved. Then, the brake pad 10 is pushed against the brake disk 3 to obtain the braking force of a wheel 2. The structure is thus simple, and can be freely mounted on the existing vehicle.