To provide a seal structure of fluid pipe capable of obtaining enhance ment of the working easiness and a stable sealing performance.

The sealing structure of fluid pipe includes a seal ring 3 in an endless ring form having approx. a circular section, wherein since the inside diameter in non-compressed state is set greater than the outside diameter of a spigot part 20, there is no need to mount to the spigot part 20 upon widening the bore of the seal ring 3. A socket part 10 is furnished continuously with a provisionally accommodating part 11 where the seal ring 3 in non-compressed state intrudes, an accommodation part for sealing 12 which is formed in a position nearer the backmost of the provisionally accommodating part 11 and where the seal ring 3 in the compressed state intrudes, and a tapered portion 13 which is provided between the provisionally accommodating part 11 and the accommodation part for sealing 12 and whose diameter reduces as going toward the accommodation part 12. When a push ring 4 is intruded to the socket part 10, the seal ring 3 in the provisionally accommodating part 11 is intruded toward the accommodation part 12.