Abstract: A calibration disk for calibrating a sensitivity of a surface defect tester, according to the present invention, comprises n (n is an integer equal to or larger than 2) false defect rows each including 3 or more false defects each formed in a radial or peripheral direction provided in the peripheral direction of the calibration disk at a predetermined angle pitch. The false defects of each false defect row take in the form of protrusions or recesses having substantially the same size, adjacent ones of the false defects are physically separated by a predetermined distance larger than a width of a laser spot and the false defects of a certain one of the false defect rows are different in size from the false defects of other false defect rows.