A capsule endoscope is swallowed by a patient, to capture images from inner wall surfaces of patients digestive tract, while detecting imaging positions of the capsule endoscope. A doctor observes the images captured by the capsule endoscope, to select an aimed point image that contains a portion suspected of a lesion, and some images that represent pass points on an insertion route of a balloon endoscope. While a probing tip of the balloon endoscope is being inserted into the patient for the sake of thorough examination of the suspected portion, a degree of similarity between an image captured by the balloon endoscope and an image of a destination point, which is one of the pass points and the aimed point, is detected to judge by the similarity whether the probing tip has reached the destination point or not. So the doctor can get the probing tip to the aimed point easily.
