Endoscope insertion assistant probe and applicable endoscope apparatus therefor

1. An endoscope insertion assistant probe comprising: a flexible, elongated probe that detects an inserted shape of the probe at least when the probe is protruded from a distal end of an insertion portion of an endoscope in an insertion direction, the probe including; plural shape detecting elements for generating or detecting a magnetic field, plural signal lines that are connected to the plural shape detecting elements, an elongated core to which the plural detecting elements are securely fixed at predetermined intervals, and an outer sheath that houses the shape detecting elements, the signal lines and the core; and a distal end guiding element that is arranged at a distal end portion of the probe, the distal end guiding element being made of a thin-film resin member having an outer surface coated with a hydrophilic lubricant and expandable by fluid, the distal end guiding element having a diameter larger than that of the probe and smaller than a minimum diameter of a body cavity when the distal end guiding element is fully expanded; wherein the endoscope insertion assistant probe is inserted into the body cavity prior to insertion of the insertion portion of the endoscope into the body cavity to assist the insertion of the endoscope; and the endoscope is inserted over the flexible, elongated probe.