Vehicular disc brake

The vehicular disc brake comprises a caliper bracket 3, a caliper body 6 attached to the caliper bracket 3, and friction pads 7, 7 disposed on both sides of a disc rotor 2, and the caliper body 6 comprises an action part 6a provided with cylinder holes 6f, 6g through which a large-diameter piston 10 and a small-diameter piston 11 are inserted, and a bridge part 6c extending across the outer periphery of the disc rotor 2. Thinned parts 6n, 6p are provided respectively in positions corresponding to the pistons 10, 11 in a disc-radially inner wall 6i of the bridge part 6c. The volume of the thinned part 6b corresponding to the large-diameter piston 10 on the disc turn-out side when the vehicle is moving forward is less than the volume of the thinned part 6p corresponding to the small-diameter piston 11 on the disc turn-in side.