PURPOSE: To provide a synthetic resin pipe connector for constituting an assembly type jungle gym for infants by connecting many cardboard pipes to each other which is simplified in the construction of metal molds for production thereof, is tough and has a good assembling characteristic.

CONSTITUTION: Adapter-like vertical members 3 are projected from a central member 17 and horizontal members 8, 8a having a cruciform shape are projected and formed orthogonally therewith respectively. Thick parts 7 are formed in the root parts of these horizontal members 8, 8a. The cruciform vertical walls 5 of these thick parts 7 are formed thick nearly over the overall height exclusive of slight parts at both top and bottom end edges in their height direction.