An inspection system includes circuitry configured to determine whether a predetermined pattern is present in a master image of an inspection target object; acquire an inspection target image of the inspection target object from an image captured by an image capturing device; compare the master image of the inspection target object with the inspection target image, to inspect the inspection target object; and switch a threshold value used in comparing the master image with the inspection target image of the inspection target object depending on a determination result of determining whether the predetermined pattern is present in the master image of the inspection target object.