To provide a method and a device for correcting a deformed cross section strip capable of uniformly correcting the deformed cross section strip without reducing working efficiency of the correction.

A deformed cross section strip 2 formed with a plurality of thick plate parts 9 and thin plate parts 10 in the width direction is placed and stretched between an inlet side bridle roll 3 and an outlet side bridle roll 4. In a method for correcting the deformed cross section strip 2, in which tension is given to the deformed cross section strip 2 placed and stretched between the inlet side bridle roll 3 and the outlet side bridle roll 4 for correcting it, the tension given to the deformed cross section strip 2 is controlled by the inlet side bridle roll 3 and the outlet side bridle roll 4 so that a change amount of strip width before passing the inlet side bridle roll 3 and after passing the outlet side bridle roll 4 could be constant.