To solve such problems that large residual stress is present in a material after straightening with the conventional tension leveler and subsequent working of cutting, printing and the like is difficult because the tension leveler uses rollers, bends the material and straightens it.

Straightening by tension is performed by pressurizing both front surface and back faces of a metallic strip sheet between the inlet and outlet bridle rolls of the tension leveler. The residual stress of the material after straightening the shape is reduced because bending is not applied to the material in tension straightening process.