Mutual compatibility is established between the measurement with a high magnification and the measurement in a wide region. A pattern measurement apparatus is proposed which adds identification information to each of fragments that constitute a pattern within an image obtained by the SEM, and which stores the identification information in a predetermined storage format. Here, the identification information is added to each fragment for distinguishing between one fragment and another fragment. According to the above-described configuration, it turns out that the identification information is added to each fragment on the SEM image which has possessed no specific identification information originally. As a result, it becomes possible to implement the SEM-image management based on the identification information.