PROBLEM TO BE SOLVED: To provide a parental relation type endoscopic system equipped with a secondary endoscope reduced in damage fear even if abraded with the treatment tool erection stand of a master endoscope by coating the curved part of the secondary endoscope with an outer skin made of a thermoplastic elastomer under a preset condition, having high durability, low in the quantity of curving force, causing no wrinkles in curving and improved in the insertion properties with the master endoscope.SOLUTION: The secondary endoscope 2 of the parental relation type endoscopic system includes a curved pipe 32 comprising a plurality of connected curved pieces 43 and a curved part 17 having an inner diameter larger than the outer diameter of the curved pipe 32 and is equipped with the outer skin 31 formed of the thermoplastic elastomer directly coating the curved pieces 43 and, when the outer diameter of the curved pipe 32 is set to D, the inner diameter of the outer skin 31 is set to d, the wall thickness of the outer skin 31 is set to t and the single side clearance between the curved pipe 32 and the outer skin 31 is set to X, the relation of 0.07&geX/D>0 and t&le0.4 is held.
