1. An endoscopy system comprising: a capsule endoscope swallowed by a test body to capture first kind of images from internal portions of the test body; an image processor for processing image data of the first kind of images, to display the first kind of images on a monitor for a doctor to interpret them; a flexible endoscope having a flexible inserter with an imaging device, said flexible inserter being inserted in the test body to capture second kind of images by said imaging device when the doctor finds it necessary to make a thorough examination of an aimed point inside the test body as a result of interpretation of the first kind of images; an aimed point selection device for selecting an aimed point image that contains said aimed point from among the first kind of images in response to an operation by the doctor; a similarity detection device for detecting similarity between said aimed point image and the second kind of images as captured by said imaging device while said flexible inserter is being moved toward said aimed point; a position information obtaining device for obtaining information on a relative position of said imaging device of said flexible endoscope inside the test body on the basis of the similarity detected by said similarity detection device; a display device for displaying the information on the relative position of said imaging device; a pass point selection device for selecting at least a pass point image from among the first kind of images, said pass point image being representative of a pass point on a route from an inlet of said flexible inserter to said aimed point, wherein said similarity detection device further detects similarity between said pass point image and the second kind of images while said flexible inserter is being inserted into the test body, and said position information obtaining device obtains the information on the relative position of said imaging device to said pass point or to said aimed point on the basis of the similarity between said pass point image and the second kind of images or the similarity between said aimed point image and the second kind of images, respectively; a first image characteristic value taking device for taking image characteristic values respectively from said aimed point image and said pass point image; and a second image characteristic value taking device for taking image characteristic values from the second kind of images, wherein said similarity detection device detects the similarity between said pass point image and the second kind of images by calculation using the image characteristic values of said pass point image and the second kind of image, and the similarity between said aimed point image and the second kind of images by calculation using the image characteristic values of said aimed point image and the second kind of image.