The object of the invention is to provide a defect inspection method, a defect inspection system, and a defect inspection program, in which the inspection time for the object to be inspected and identifiable as a linear or band-like one is so very short that the operation time and tact time can be cut down, and which prevents misidentification even when there is distortion or deformation in the object, thereby making precise defect inspection possible. In the defect inspection method, system and program, the luminance and the number of pixels in the widthwise direction of the image of the object to be inspected such as the edge portion of a semiconductor wafer, wherein the image is identifiable as a linear or band-like one, are summated up, and the object is determined as defective when the value of the summation is below a reference value.