A linking pin made of elastic plastic having linking pin halves is used to link segments in the longitudinal direction to assemble a rehabilitation pipe. The linking pin includes a tubular portion having on its outer periphery surface first and second protrusions separated by a distance of twice the thickness of the side plate of the segment and a rear protruding portion that enlarges in diameter due to elasticity. The linking pin is inserted into one segment and the other segment so that the side plates of both the segments come between the first and second protrusions. The linking pin is then enlarged in diameter due to elasticity to fit the side plates between the first and second protrusions and link both the segments in the longitudinal direction. The linking pin that is enlarged in diameter can be reduced in diameter to unlink both the segments.