To provide a water sealing structure capable of securely preventing water from leaking into a shaft and a manhole even if soil moisture flows between an existing tube and a regenerated tube by the cracking of the existing tube.

In this water sealing structure, the resin long regenerated tube 13 is inserted into the existing tube 11 and the regenerated tube 13 is fitted to the inner peripheral surface of the existing tube 11. A water sealing layer 23 formed of a water expansible rubber and/or a water expansible elastomer sealing the outer peripheral surface 13a of the regenerated tube 13 and the inner peripheral surface 11a of the existing tube 11 is formed at the end part of the regenerated tube 13 between the regenerated tube 13 and the existing tube 11.