To provide a disk brake that is small in dragging brake force in time of releasing a braking action, and hard to cause any unequal abrasion in disk rotor, besides being inexpensive in cost.

A sense of energizing force separating two outer pad pressing parts 19, 20 and an outer pad 13 from each other at a centroid position of this outer pad 13 in the radial direction of a disk rotor 11 in time of braking action, is added to an interval between the outer pad pressing parts 19, 20 of a sliding cylinder 15 and a backside of this outer pad 13, and at the time of releasing the braking action, such a spring member 22 as separating these outer pad pressing parts 19, 20 and the outer pad 13 from each other as far as the specified value δ2 (smaller than a piston return stroke by a seal ring 21) is set up there.