PURPOSE: To provide a disk brake that is able to make improvements in durability and to prevent any camber from occurring.

CONSTITUTION: A wear sensor 12 is installed in space between a pair of claw parts 7 and 7 of an outer pad 2, and this wear sensor 12 is composed of a mounting part 15 to the outer pad 2, two extension parts 16 extending in an end of the outer pad 2 from this mounting part 15, and vibration pieces 17 flectionally formed on a tip side of this extension part 16 in direction of a disk 1 so as to go round the end of the outer pad 2, and each bulge 20 jutting out in direction of separating from the outer pad 2 and extending in an elongation direction of this extension part 16 is installed in this extension part 16. This extension part 16 means that rigidity in the wear sensor 12 grows larger in consequence. Accordingly, such a fear that a car is produced in this extension part can be checked, and durability of the wear sensor 12 is therefore improved. Supposing the extension part 16 is set to lee longer and the width narrower respectively, the wear sensor 12 comes to be tolerable, so even in the case where there is a restriction in the installing space, it is easily resistible in consequence.