An endoscope insertion shape detecting device of the present invention comprises an insertion shape detection portion for detecting an insertion shape of an endoscope insertion portion, an insertion shape image generation portion for generating an insertion shape figure of the endoscope insertion portion according to the insertion shape, a marking processing portion for carrying out a control to add a mark to the insertion shape figure for output as a control for the insertion shape image generation portion in a first observation for the subject, a memory portion for storing subject information, the insertion shape figure, and information on a position to which the mark is added in the insertion shape figure, and a position detection information output portion for outputting position detection information when a distal end portion of the insertion shape figure overlaps the mark position information in second observation made for the same subject.
