BRAKE DEVICE, BRAKE SYSTEM, AND VEHICLE

A brake device comprises a main braking caliper body, a brake pad part including a first brake pad and a second brake pad that are arranged at one side and another side of the main braking caliper body and have first surfaces facing each other, a main braking piston pressurizing second surfaces of the first brake pad and the second brake pad to shorten a distance between the first brake pad and the second brake pad, a parking caliper body coupled to the main braking caliper body and including a locking part caught by the second surface of the first brake pad and a parking piston installed on the parking caliper body and pressuring the second surface of the second brake pad, when the parking piston pressurizes the second brake pad, the locking part of the parking caliper body moves the first brake pad toward the second brake pad.