A color sorting apparatus capable of displaying images of granules picked up by a CCD sensor on a panel and performing sensibility control of defective granules while observing the displayed images is provided. The color sorting apparatus comprises a contour processor for outputting contour binary data from the picked-up images and a contour threshold, a first defective determination circuit for outputting the defective part of the granule having a predetermined area or more of part exceeding a first threshold in the form of first defective pixel binary data, and a second defective determination circuit for outputting the defective part of the granule having a part exceeding a second threshold being greater than the first threshold in the form of second defective pixel binary data. The first defective pixel binary data are displayed on a monitor for thin coloration. The second defective pixel binary data are displayed on a monitor for partial coloration. The, contour binary data and, the first and second defective pixel binary data are combined, and the combined data are displayed on a granule display monitor. An operator can adjust the respective thresholds while observing those displays.