1. An inspection apparatus comprising: an illumination optical system which illuminates an object with light; a detection optical system which detects light from the object; a display system which displays a defect candidate group so as to correspond to coordinates on the object, based on a detection result from the detection optical system; an input system for selecting a defect candidate having an arbitrary detection recall factor from the defect candidate group displayed on the display system; and a processing system programmed to perform the process functions of: i) in the case where an arbitrary defect candidate selected from the defect candidate group by the input system is determined as a false defect, classifying the defect candidate group into a defect or false defect based on a detection recall factor of the determined false defect; and ii) obtaining a threshold for determining whether there is a defect on the object based on the classification result, wherein the display system is configured to reflect the classification result, and the input system is capable of selecting a plurality of arbitrary defect candidates on the display system.