DISC BRAKE DEVICE

PROBLEM TO BE SOLVED: To simplify the structure, lower the cost, and prevent the irregular abrasion of a brake pad without increasing dimension of a device by setting a sliding resistance between a cylinder and a piston of each cylinder-piston mechanism larger, as the piston-cylinder mechanism is positioned closer to a turn-in side of a disc rotor. SOLUTION: Since a necessity of offsetting a cylinder is eliminated by adjusting seal width and a seal tightening margin and changing seal raw material so as to change the sliding resistance, a necessity of changing dimension of a piston, a necessity of adjusting oil pressure to be applied to each piston, and a necessity of adding other device are eliminated, and cost is not raised. Since sliding resistance of each cylinder is set larger, as a device is positioned closer to a turn-in side of a disc rotor, pushing force of a brake pad of a turn-in side (a second) piston is restricted, and the pushing force of the brake pad to the disc rotor can be easily evened so as to prevent the irregular abrasion of the brake pad.