Abstract: An endoscope which has small bending resistance and is hard to be damaged or broken even when it is repeatedly used is disclosed. The endoscope includes a flexible insertion section 2 and an operation section 7 provided on the proximal end of the insertion section 2. The insertion section 2 has a sheath constructed from an outer layer 382 and the like, and elongated members such as an image guide 31 and light guides 32, 32 and the like are housed in lumens in the sheath. Further, each light guide 32 has an optical fiber bundle and a protective sheath 321 for protecting the optical fiber bundle. In the interior space of the protective sheath 321, a lubricant 5 containing a silicone oil and a solid lubricant is provided. The solid lubricant contains at least one of boron nitride, poly tetrafluoroethylene, and molybdenum disulfide. The solid lubricant is preferably formed into powder having an average grain size of 0.1 to 15 ?m.

Abstract: An endoscope which has small bending resistance and is hard to be damaged or broken even when it is repeatedly used is disclosed. The endoscope includes a flexible insertion section 2 and an operation section 7 provided on the proximal end of the insertion section 2. The insertion section 2 has a sheath constructed from an outer layer 382 and the like, and elongated members such as an image guide 31 and light guides 32, 32 and the like are housed in lumens in the sheath. Further, each light guide 32 has an optical fiber bundle and a protective sheath 321 for protecting the optical fiber bundle. In the interior space of the protective sheath 321, a lubricant 5 containing a silicone oil and a solid lubricant is provided. The solid lubricant contains at least one of boron nitride, poly tetrafluoroethylene, and molybdenum disulfide. The solid lubricant is preferably formed into powder having an average grain size of 0.1 to 15 &mgr;m.

Abstract: In an endoscopic optical fiber bundle, cutouts (15a) are formed near an end portion of helical tube (15) and the area with the cutouts is placed over socket (12), with a string-like member (16) being passed through the cutouts (15a) to be wound onto the outer surface of the helical tube (15) so that the socket (12) is tightly bound to the helical tube 15.