An apparatus for dressing a wafer polishing pad, including a disk-shaped dresser, an arm, and a control unit. The disk-shaped dresser is configured to be pressed against the polishing pad which rotates in a circumferential direction. The dresser is configured to rotate in a same direction as the polishing pad rotates due to frictional force generated between the dresser and the polishing pad. The arm is configured to support the dresser rotatably and to press the dresser against the polishing pad. The control unit is configured to control the arm to position the dresser such that a peripheral edge portion of the dresser is positioned outside a peripheral edge portion of the polishing pad by a predetermined distance.