PURPOSE: To securely prevent deformation and breakage of members of a coupling due to an earthquake or the like by disposing a damper capable of being compressively deformed by a water pressure between annular anchoring members fixed to the ends of a pair of culverts to be connected and flexible water stoppers provided around the fixing members.

CONSTITUTION: A coupling 1 is provided with a fixing members 2, 2' fixed at the opposite surfaces of a pair of culverts. A large-diameter cylindrical body 9 is loosely fitted to a bar 7 of a durable member 5 for connecting the fixing member 2, 2' within a predetermined range in such a manner as to be brought into or out of relative contact with each other. A primary and a secondary flexible water stopper 10, 11 are disposed coaxially on the outer periphery of an annular row of the cylindrical body 9. An annular damper 15 such as foam rubber compressively deformed if a water pressure therein exceeds a given value due to an earthquake or the like is provided in a space 14 defined by the anchoring members 2, 2' and the primary and secondary flexible water stoppers 10, 11. Consequently, it is possible to restrain an increase in water pressure, and prevent deformation and breakage of the members of the coupling.