A disk brake capable of improving work efficiency when a friction pad is attached to a mount member. Ear portions of a friction pad are inserted in pad guides of a mount member. A side push spring, which pushes the friction pad in a rotational direction of the disk, is provided at the friction pad. A pad spring is disposed between the mount member and the friction pad. The pad spring includes a guide plate portion and a guide protruding portion. The guide plate portion is attached so as to be able to abut against the pad guide of the mount member, and functions to guide the friction pad in an axial direction of the disk. The guide protruding portion extends from an outer-side portion of this guide plate portion toward an outer side in the disk axial direction. The guide protruding portion is inclined in the disk rotational direction.