A shim plate relatively movably attached with a friction pad in a rotational direction of a disc is disposed between the friction pad and a reaction section of a caliper, a plurality of claw sections formed to extend in a radial direction of the disc at a position deviated in the rotational direction of the disc with respect to a center of pistons are formed at the reaction section, and movement restriction portions that can abut the intermediate claw section disposed at the middle of the claw sections of the reaction section are formed at a surface of the shim plate opposite to the reaction section in the radial direction of the disc.