bush 15 and in the case of this embodiment comes to a stop in a state as shown in fig1 when it comes into contact with the flange part 11a of the auxiliary slide pin 11 then a further sliding movement of the caliper 3 is restricted by a relatively great sliding resistance due to the rubber bush 15 to preclude the problem of knock back or the like further in this embodiment the rigid sleeve 13 is made of a metal however the invention is not limited to this and the rigid sleeve 13 may be made of a resin or other plastic material furthermore if rust is formed between the slide pin 11 and the sleeve 13 thereby restricting sliding movement therebetween the caliper 3 can move slightly to return to the repose position due to the sliding motion between the sleeve 13 and the rubber bush 15 or due to elastic restoration of the rubber bush 15 therefore even under such circumstances the friction pad is never dragged by the disc thus the sliding motion between the sleeve 13 and the bush 15 is reversible in this embodiment example the auxiliary slide pin is arranged as shown in fig2 in a manner similar to the arrangement of embodiment example 1 on the side of the main slide pin the sliding resistance is arranged to vary with increase in the extent of the sliding movement of the caliper in other words the sliding resistance of the main sliding pin and that of the auxiliary slide pin are arranged to be.