To prevent the deterioration of braking characteristics, the occurrence of vibration and the deterioration of assembling ability, which are caused by unbalance in weight of a carrier, so as to enhance the durability.

One 23 of a pair of support parts 23, 24 which are provided on a carrier 1 secured to a stationary part of a vehicle is provided at the distal end of an arm part 28 extended inward of the vehicle from the carrier 1, and cylindrical parts 27 provided on both sides of a caliper body 2 slidably fitted on pin parts 25a of pin bolts 25 which are laid between both support parts 23, 24 from the outside of the vehicle and are fastened and fixed, through the intermediary of sleeves 26. Thus, a pin slide mechanism 3 is obtained. A caliper which is heavy due to incorporation of a motor-driven device is stably supported on both support parts 23, 24 in a center beam manner so as to prevent the caliper from being inclined during braking in order to restrain the increase of a drag torque or the deterioration of a judder characteristic, and to restrain the occurrence of vibration caused by a pin clearance of the pin slide mechanism 3.