1. A method for classifying defects, comprising: obtaining a defect image by taking a picture of a sample; extracting a characteristic amount of defects from the defect image; preparing at least one type of classification model which is a combination of rule-based classification and learning type classification to calculate the likelihood that the extracted defects belong to a classification class by using information on the extracted characteristic amount of the defects; and classifying the defects of which characteristic amount is extracted by the at least one type of classification model.