A bending operation lever 20, a cylindrical member 50, and a seal unit 30 having an elastic member 60 are provided. The elastic member 60 is a longitudinal axis of the cylindrical member 50 with respect to the outer periphery 50 g of the cylindrical member 50. The fixing portion 32 is fixed circumferentially along the direction N, and extends substantially concentrically with the fixing portion 32 from the outer periphery 32g of the fixing portion 32 to the outside in the radial direction K of the fixing portion 32. A portion 33 extending from the outer periphery 32g has an extending portion 100 extending at a predetermined angle θs.湾曲操作レバー２０と、筒状部材５０と、弾性部材６０とを有するシールユニット３０と、を具備し、弾性部材６０は、筒状部材５０の外周５０ｇに対して、筒状部材５０の長手軸方向Ｎに沿って周状に固定された固定部３２と、固定部３２の外周３２ｇから固定部３２の径方向Ｋの外側に固定部３２と略同心円状に延出するとともに、固定部３２の外周３２ｇから延出する部位３３が所定の角度θｓを有して延出する延出部１００と、を有する。
