To provide a tube connecting section of an endoscope easily and surely connecting and fixing a flexible tube disposed in the endoscope to a connecting tube even in a narrow space.

A projection 172 is formed near a base part of an outer circumferential tapered face 171 of the connecting tube 17, a plurality of slits 183 reaching the tip are formed in parallel to the axis at the tip side half part of a tube pusher ring 18 fitted around the connecting section between the flexible tube 11-16 and the connecting tube 17 from the side of the flexible tube 11-16, and a small diameter part 182 extending across the projection 172 of the connecting tube 17 and abutting on the rear face of the projection 172 is formed by elastically deforming the tip side half part of the tube pusher ring 18 on the internal circumferential part of the tip part of the tube pusher ring 18.