PROBLEM TO BE SOLVED: To reduce the load applied to a split mold by reducing the tilting force for demolding even when the tilting arm of the split mold is made long. SOLUTION: In a mold for molding a plastic pipe constituted so that inner molds 1a, 1b for molding the receiving port of the plastic pipe are set to split molds in the peripheral direction of the mold and the respective split molds 1a, 1b are tilted in the diameter contracting direction of the receiving port of the plastic pipe from the inner surface molding position of the receiving port of the plastic pipe to be subsequently made possible to retreat and move along a core, the length of the arms 1d supporting the split molds 1a, 1b in a tiltable manner is made sufficiently large so as to become a movement not generating the interference with the recessed part 11 of the inner surface of the receiving opening 10 at the time of tilting of the mold and tilting energizing members 8a, 8b are provided in the split molds 1a, 1b in the core direction.