Patent ID: 8317685

Claim:
A rotatable operation device for an endoscope, comprising: a fixed shaft projected outward from an operating portion; a cylindrical shaft projected from a rotatable operating member, the cylindrical shaft being rotatably fitted on the fixed shaft, the cylindrical shaft having a proximal end portion extending from the rotatable operating member and a distal end portion positioned within the operating portion, and an end side surface of the distal end portion of the cylindrical shaft contacting a fixed surface defined inside the operating portion, the operating portion having an airtight structure so that an internal space of the operating portion and an internal space of the rotatable operating member do not communicate with an outside; and an air passage defined by an opening that penetrates an outer surface and an inner surface of the cylindrical shaft, the air passage being provided at the distal end portion of the cylindrical shaft, and an annular space provided between the fixed shaft and the cylindrical shaft, the annular space communicating with the internal space of the operating portion through the air passage with the end side surface and the fixed surface contacting each other.