A rehabilitating pipe is laid inside an existing pipe using segments each having coupling surfaces in the circumferential direction and the longitudinal direction of the existing pipe. The coupling surfaces in the circumferential or longitudinal direction are mutually bonded substantially across their entire surfaces via an adhesive or a sheet impregnated with an adhesive and mechanically joined to couple the segments and assemble the rehabilitating pipe. Such an arrangement makes it possible to improve the joining strength, uniformity and watertightness in the coupling portion of the segments.