Pipeline roundness correction device

The utility model discloses a pipeline roundness correcting device which comprises a jack, a lower ejector block arranged on a jack base and an upper ejector block arranged at the end of a jack push rod, a support is arranged on one side of the jack, an outer ejector block is arranged on the support, and the bottom face of the lower ejector block, the top face of the upper ejector block and the bottom face of the outer ejector block are all arc-shaped faces. The arc-shaped surface radiuses of the bottom surface of the lower ejection block and the top surface of the upper ejection block are equal to the inner circle radius of a to-be-calibrated pipe body and are oppositely arranged in a bracket shape, the arc-shaped surface radius of the bottom surface of the outer ejection block is equal to the outer circle radius of the to-be-calibrated pipe body, the bottom surface of the outer ejection block and the bottom surface of the lower ejection block are oppositely arranged in a bracket shape, and the axes are over