The utility model discloses an automatic control device of bending rollers. The automatic control device comprises a mechanical transmission device. The mechanical transmission device comprises a drawing device, transmission rollers, location rollers and the bending rollers. The location rollers are symmetrically installed on two sides of the drawing device, and the location rollers, the transmission rollers and the bending rollers are respectively installed on two sides of the mechanical transmission device at the corner position. The automatic control device is characterized in that a coder used for metering drawing length of a copper pipe is installed on a main drawing shaft, and the coder is connected with a programmable logic controller (PLC). The automatic control device has the advantages of being simple in structure, ingenious in design and capable of effectively avoiding surface pits caused by the fact that the head of the copper pipe abuts against the bending roller by adding the coder on the mechanical transmission device and enabling the PLC to conduct logic control.