There are many different causes of air drum brake judder noise in commercial vehicles. This study set out to identify those causes from the perspective of brake structure, not taking the environment into account. For that purpose, the investigator measured vibrations and noises in case of brake judder noise and analyzed their causes. The structural vibrations of the brake were analyzed to identify the causes with an experimental method involving O.D.S. (Operational Deflection Shape) analysis and model testing. In an effort to find directions for improvement with an analytical method, the investigator modeled the brake system in an analytical manner, correlated it with the experiment results, and tested directions for improvement in an analytical fashion. The structural rigidity of the brake that had been tested analytically was increased so that the generation frequency and structural vibration frequency of brake judder noises would not be contiguous. The parts of high structural rigidity were tested for brake judder noises with a model test and vehicle test.