A disc brake includes a first casing and a second casing abutting each other to define a receiving space for partially and separately receiving a brake disc. The first casing and the second casing respectively has an axial pushing apparatus mounted therein. Each axial pushing apparatus has a first end outwardly extending through the first/second casing and a second end having a lining pad mounted thereon. The first end of each of the axial pushing apparatus is respectively connected to a lever that is connected to a brake cable. The two axial pushing apparatus inwardly moves the two brake linings to synchronously clamp the two opposite sides of the brake disc for speeding down or stop the bicycle when the brake cable pulls the lever.