And the front end portion 21 which is provided at the distal end of the insertion direction S of the insertion portion 11, a bending portion 24 of the first provided in the insertion direction of the base end side of the distal end portion 21 of the insertion section 11, the first 11 in the insertion portion provided and a curved portion 25 of the second provided in the insertion direction of the base end side of the bending portion 24, from the distal end of the insertion direction S of the tip 21, to the proximal end of the insertion direction S of the curved portion 25 of the second e length along the insertion direction S of the is characterized in that it is set to 73mm~100mm.挿入部11の挿入方向Sの先端に設けられた先端部21と、挿入部11における先端部21の挿入方向基端側に設けられた第1の湾曲部24と、挿入部11における第1の湾曲部24の挿入方向基端側に設けられた第2の湾曲部25と、を具備し、先端部21の挿入方向Sの先端から、第2の湾曲部25の挿入方向Sの基端までの挿入方向Sに沿った長さeは、73mm~100mmに設定されていることを特徴とする。
