The endoscope 1 includes a grasping portion 3A and an operation portion 3 having a grasping assisting surface 35a for placing a finger when an operator grasps the grasping portion 3A, an insertion portion 2 provided with a bending portion 2b on the distal end side, At least one knob 5 that is provided on one side of the operation unit 3 and that bends the bending unit 2b by rotating about the rotation shaft 5a, and a fluid control button arrangement unit 32 that forms the upper side of the operation unit 3. And at least two air / water supply buttons 6a and a suction button 6b arranged in parallel in the longitudinal axis direction of the operation unit 3. The switch root portions 6ar and 6br of the buttons 6a and 6b are normal to the rotation center axis. The outermost diameter locus 5S of the up-and-down knob 5 projected on the flat surface and the fluid control button arrangement portion 32 are arranged so as to be positioned between two intersections P1 and P2.内視鏡１は、把持部３Ａ及び術者が把持部３Ａを把持した際に指を配置する把持補助面３５ａを有する操作部３と、先端側に湾曲部２ｂを設けた挿入部２と、操作部３の一側面に設けられ、回転軸５ａを中心に回転操作して湾曲部２ｂを湾曲させる少なくとも一つのノブ５と、操作部３の上側を構成する流体制御ボタン配置部３２から突設し、操作部３の長手軸方向に並列される少なくとも二つの送気送水ボタン６ａ、吸引ボタン６ｂと、を備え、各ボタン６ａ、６ｂのスイッチ根本部６ａｒ、６ｂｒを、回転中心軸を法線とした平面に投影した上下用ノブ５の最外径軌跡５Ｓと流体制御ボタン配置部３２とが交差する二つの交点Ｐ１、Ｐ２間に、位置するように配置した。
