PROBLEM TO BE SOLVED To obtain a distal end connection structure of a small diameter endoscope insertion portion.SOLUTION: The distal end portion connection structure of the endoscope insertion portion in which the bending tube (2) on the distal end side of the insertion portion and the flexible tube (1) on the operation portion side are connected by the connecting pipe (31, 32) , The connecting pipe has a flexible tube distal connecting tube (31) fixed to the distal end portion of the flexible tube and a bending tube rear end connecting pipe (32) fixed to the rear end portion of the bending tube , The annular concave portion (31 d) is formed in the outer circumference of the flexible tube distal end connection tube, and the distal end portion end face (13 a) of the flexible tube outer skin (13) positioned on the outer circumference of the flexible tube , And the rear end portion end face (24a) of the curved tube outer skin (24) positioned on the outer periphery of the bending tube are located in the annular recessed portion of the flexible tube distal end connection tube, and do not overlap in the radial direction End connection structure of the endoscope insertion portion.(FIG.【課題】小径化した内視鏡挿入部の先端部接続構造を得ること。【解決手段】挿入部先端側の湾曲管(2)と、操作部側の可撓管(1)とが繋ぎ管(31、32)で連結されている内視鏡挿入部の先端部接続構造において、繋ぎ管は、可撓管の先端部に固定された可撓管先端繋ぎ管(31)と、湾曲管の後端部に固定された湾曲管後端繋ぎ管(32)とを有すること、可撓管先端繋ぎ管の外囲には、環状凹部(31d)が形成されていること、及び、可撓管の外周に位置する可撓管外皮(13)の先端部端面(13a)と、湾曲管の外周に位置する湾曲管外皮(24)の後端部端面(24a)とが、可撓管先端繋ぎ管の環状凹部内に位置していて、径方向にオーバラップすることなく対向している内視鏡挿入部の先端部接続構造。【選択図】図3
