To provide a disk brake which prevents stress concentration from occurring in parts that become nodes of vibration modes of a splash guard.

First regions S1 of peripheral edges of notch corner parts 7a at both sides of at least a notch 7 astride the nodes M0 of the vibration modes of the splash guard 4 and a second region S2 including an attaching surface 6 at the center of plate surface and its peripheral part are structured as high rigidity parts 10. Therefore, stress that tends to concentrate on the nodes M0 of the vibration modes is dispersed at the high rigidity parts 10 of these first regions S1 and second region S2 and can widely be dispersed to general surfaces.