The invention discloses an automatic reinforcing steel bar binding machine. The automatic reinforcing steel bar binding machine comprises a machine frame, a wire binding disc mechanism, a power mechanism, a wire conveying mechanism, a wire cutting mechanism, a jaw and guiding mechanism, a wire bending mechanism and a wire twisting mechanism, wherein the wire binding disc mechanism, the power mechanism, the wire conveying mechanism, the wire cutting mechanism, the jaw and guiding mechanism, the wire bending mechanism and the wire twisting mechanism are arranged on the machine frame; and the seven mechanisms are deployed reasonably, and on the one hand, operation such as wire conveying, wire cutting, wire bending and wire twisting can be achieved rapidly and continuously through one hand, the working efficiency is greatly improved, even untrained workers can easily and proficiently operate, labor cost is reduced, and one the other hand, binding is tight to achieve the effect of manual binding. In addition, the automatic reinforcing steel bar binding machine is small and exquisite, portable, flexible, low in cost, high in adaptability, free from charging, waterproof, adaptable to severe environment and easy to promote and popularize.