An endoscope 1 having an insertion portion 12 an elongated, which is inserted into the duodenum 90, a bendable bending portion 16 is provided, insertion of the distal end 17 is the tip side of the curved portion 16 of the insertion portion 12 independently of the bending of the bending portion 16, and the viewing direction of the objective lens 34 which is a radial direction of the insertion portion 12, a parallel one side 17k to the central axis P of the insertion portion 12 in the circumferential direction along the insertion direction W of 12 I comprises a balloon and 10d of the fourth balloon 10a~ first moved in parallel to the S.十二指腸90内に挿入される、湾曲自在な湾曲部16が設けられた細長な挿入部12を有する内視鏡1と、挿入部12の湾曲部16よりも先端側である先端部17の挿入部12の挿入方向Wに沿った周方向の挿入部12の中心軸Pに平行な一側面17kを、湾曲部16の湾曲とは別個に、挿入部12の径方向となる対物レンズ34の視野方向Sに対し平行移動させる第1のバルーン10a~第4のバルーン10dとを具備する。
