To provide a tip part of an extra-fine electronic endoscope without bringing an electrical insulating tape wound around an imaging unit holder cylinder into contact with an operation wire on the loose side even if a curved part is firmly curved and without occurrence of the insulation failure in an imaging unit.

The maximum tilting angle θ between a joint ring 14a at the top end of a curved tube formed by connecting a plurality of joint rings 14 tiltably between adjacent joint rings and a second joint ring 14b adjacent to the joint ring 14a is set in such a range that the operation wire 17b on the loose side is not brought into contact with the electrical insulating tape 12 even if the operation wire 17b on the loose side is deviated inward by the tilting.