In fist type of disc brakes, pin type sliding with boots to protect them is usually adopted for calipers. This has proven effective for preventing rusting in the northern part of the American continent and Europe. The recent tendency to improve the fuel economy is demanding reduced drag for disc brakes. In floating type disc brakes some amount of drag is inevitable, but in the AD brake we have been successful in reducing the torque to a minimum without adverse effects. Main points in reducing drag are: adoption of duplicate pins, anchor plate of high rigidity, various methods to insure parallel wear pattern of pad linings, selection of pad lining material, backing plate thickness and position of spigot holes, etc.Design details and results of laboratory and vehicle tests are explained.