The invention provides an automatic pipe bending machine. The automatic pipe bending machine comprises a machine body, wherein a steel tube conveying rail is arranged on the machine body, a clamping block is arranged at the right end of the steel tube conveying rail, a fixing pillar is arranged on the right side of the clamping block, a bending pillar is arranged at the rear end of the fixing pillar, a rotation plate is arranged at the bottom of the fixing pillar, the fixing pillar is arranged at the center of the rotation plate, the bending pillar is arranged on the edge of the rotation plate, a rotation motor is arranged at the bottom of the rotation plate, the rotation plate is driven by the rotation motor to rotate, and the right end of the steel tube conveying rail is located between the fixing pillar and the bending pillar. The automatic pipe bending machine bends air conditioning pipes through rotation between the fixing pillar and the bending pillar, and loads and clamps the air conditioning pipes through the steel tube conveying rail and the clamping block, automatically performs bending work, retracts the fixing pillar, the bending pillar, the rotation plate and the rotation motor into the machine body when the fixing pillar, the bending pillar, the rotation plate and the rotation motor are not needed to work by arranging a lifting air cylinder, and prevents the fixing pillar, the bending pillar, the rotation plate and the rotation motor from being polluted by dust and abraded due to inattention of workers, and therefore use life of the automatic pipe bending machine is prolonged.