To provide a disc brake that can be efficiently cooled.

This disc brake has a disc 1 with its peripheral edge formed into a flat circular crown, and two facing brake pads 4 fitted to press the disc 1 inserted between them. A plurality of inlets 3 are radially arranged at the inner peripheral edge of the disc 1. A plurality of inlets 3 are regularly distributed with respect to the rotating direction of the disc 1 and preferably bent onto the rear side. Each brake pad 4 rubbing the face of the disc 1 is provided with an arcuate groove 2 formed in a direction related to the inlet 3 from a mutual interference area to a pad outline. An air passage is formed in the mutual interference area of the inlet 3 and groove 2, and a brake unit is cooled by air flow.