An endoscope system includes an image recording section configured to record three-dimensional image information of a subject, a lumen-organ extracting section configured to extract a predetermined lumen organ from the three-dimensional image information, a virtual-endoscopic-image generating section configured to generate a virtual endoscopic image from a predetermined visual point position with respect to information concerning the extracted predetermined lumen organ, an image pickup section configured to pick up an image of an inside of the predetermined lumen organ, a position-information acquiring section configured to acquire position information of a distal end of an insertion section, a lumen-diameter-change-amount detecting and comparing section configured to detect a change amount of a lumen diameter on the basis of the position information of the distal end of the insertion section, an image-change-amount detecting section configured to detect a change amount of a feature section concerning the predetermined lumen organ, and an information recording section configured to record, on the basis of detection results of the detecting sections, predetermined information including a position of the distal end of the insertion section and the virtual endoscopic image corresponding to the position of the distal end.
