The endoscope includes at least one of a plurality of endoscope built-in objects inserted through the endoscope insertion portion extended from the endoscope operation portion, and at least one of a plurality of endoscope built-in objects, A stepped endoscope built-in object in which the outer diameter size of the stepped endoscope is different from the outer diameter size of the proximal side portion and the outer diameter of the proximal side portion is larger than the outer diameter of the distal side portion, A bending portion is provided between the proximal end and the distal end, and a plurality of endoscope built-in objects and a distal side portion of the built-in stepped endoscope are inserted through a predetermined inner diameter A distal end side insertion portion having a hole and constituting the distal end side of the endoscope insertion portion together with the distal end portion main body, one end connected to the proximal end of the distal end side insertion portion, and another end connected to the endoscope operation portion And has a through hole having a diameter larger than the inner diameter of the installation hole for guiding the large diameter proximal side portion of the plurality of endoscope built-in objects and the stepped endoscope built-in object into the endoscope operation portion And a proximal end side insertion portion which constitutes the proximal end side of the endoscope insertion portion.内視鏡は、内視鏡操作部から延出される内視鏡挿入部内を挿通する複数の内視鏡内蔵物と、複数の内視鏡内蔵物のうちの少なくとも一つであって、先端側部の外径寸法と基端側部の外径寸法とが異なり、基端側部の外径が先端側部の外径より太径に構成された段付内視鏡内蔵物と、先端と基端とを備え、基端と先端との間に湾曲部が設けられ、複数の内視鏡内蔵物及び段付き内視鏡内蔵物の先端側部が挿通される予め定めた内径の配設穴を有し、先端部本体とともに内視鏡挿入部の先端側を構成する先端側挿入部と、先端側挿入部の基端に接続される一端と、内視鏡操作部に連結される他端とを備え、複数の内視鏡内蔵物及び段付き内視鏡内蔵物の太径な基端側部を内視鏡操作部内に導く、配設穴の内径より大径な貫通孔を有して内視鏡挿入部の基端側を構成する基端側挿入部と、を具備している。
