PROBLEM TO BE SOLVED: To provide an endoscope air supply/water supply valve which can make larger variation in the amount of actuating force at the flow channel being switched while ensuring air tightness and water tightness, and also to provide an endoscope comprising such an air supply/water supply valve.SOLUTION: An endoscope air supply/water supply valve according to the present invention comprises: a piston section extending in a rod shape； and an attachment member inserted into the piston section and attachable to an endoscope. The piston section includes a seal portion forming a hollow disc shape with a center axis of the piston section as an axis of symmetry and airtightly or watertightly shielding a space between the seal portion and the attachment member or the endoscope. The surface of the attachment member facing the seal portion includes: a first inner peripheral surface axially symmetric with respect to the center axis of the attachment member and having a diameter smaller than the diameter of the outer periphery of the seal portion； a second inner peripheral surface axially symmetric with respect to the center axis of the attachment member and having a diameter equal to or larger than the diameter of the outer periphery of the seal portion； and a connecting surface axially symmetric with respect to the center axis of the attachment member and connecting the first inner peripheral surface and the second inner peripheral surface.SELECTED DRAWING: Figure 5【課題】気密又は水密を確保しつつ、流路が切り替わる際の作動力量の変化を大きくすることができる内視鏡用送気送水弁及び内視鏡を提供すること。【解決手段】本発明にかかる内視鏡用送気送水弁は、棒状をなして延びるピストン部と、ピストン部に挿通されてなり、内視鏡に取り付け可能な取付部材と、を備え、ピストン部は、当該ピストン部の中心軸を対称軸とする中空円盤状をなし、取付部材又は内視鏡との間を気密又は水密に遮蔽するシール部を有し、取付部材のシール部と対向する面は、取付部材の中心軸に対して軸対称をなし、シール部の外周のなす径よりも小さい径を有する第１内周面と、取付部材の中心軸に対して軸対称をなし、シール部の外周のなす径と同等、又は該径よりも大きい径を有する第２内周面と、取付部材の中心軸に対して軸対称をなし、第１内周面と第２内周面とを連結する連結面と、を有する。【選択図】図５
