1. An endoscope inserting direction detecting apparatus comprising: image input means for receiving an endoscopic image from an endoscope that is inserted into a body cavity; pixel sampling means for sampling a stated pixel value from the endoscopic image received by the image input means; shape estimating means for estimating the shape of a specified area on the basis of the continuity of the distribution of pixels that indicate the stated pixel value and that are sampled by the pixel sampling means; and inserting direction determining means for determining an inserting direction within the body cavity, in which the endoscope should be further inserted, according to the shape estimated by the range shape estimating means.