A segment for rehabilitating an existing pipe has an integral structure comprised of an inner plate having an inner circumferential surface that is planar or curved with a prescribed curvature, two side plates provided upright on each side edge of the inner plate, and two end plates provided upright on each end edge of the inner plate. At least one rehabilitating plate comprising a resin sheet covers one of an outer circumferential part of the segment facing the existing pipe and the inner circumferential surface of the inner plate.