A method of manufacturing a disc brake in which a pair of pads are disposed on opposite sides of a disc. A caliper body extends over the disc. The method includes forming, in the caliper body, a prepared hole for a bore into which a piston is slidably fitted and a recess extending from a bottom portion of the prepared hole outwardly in a radial direction of the prepared hole. The bore and recess are formed by means of a core during casting. A linear passage opening is formed by cutting from an exterior surface of the caliper body so as to communicate with the recess. Thus, an opening for forming a brake fluid passage can be easily formed by machining, and the position of the opening can be determined with a high degree of freedom.