A corrugated resin elbow comprises a corrugate-shaped synthetic resin pipe wall which includes a plurality of valley portions, a plurality of ridge portions and side surfaces respectively interposed between the valley portions and the ridge portions. At least one of the valley portions and the side surfaces which is disposed on the bend small diameter side of the substantially middle portion of the pipe wall in the longitudinal direction thereof is contractingly heated and deformed to thereby work the corrugate-shaped pipe wall into a bent attitude having a given angle.