PURPOSE: To present the stock to form a tube body or a gutter like on the site by making the coil of metallic strip given the residual stress with the treatment of bending and bending back uniformly to the lateral direction.

CONSTITUTION: The residual stress is given uniformly to the lateral direction by treating the predeforming part 30 with bending and bending back after uncoiling the metallic strip 10 from the uncoiler 20. On coiling, if the tension applying to the metallic strip 11 is the usual 2-3kgf/mm2 grade, it is not operated to the direction to eliminate the applied residual stress. So, if the coil is coiled tightly as same as the usual coil, the applied residual stress is kept. On the time to form this metallic strip to the tube like or the gutter shape, it is made to curl to the lateral direction by utilizing the residual stress, so the products after forming is to have the same curvature rate. On the case that the tube is manufactured, the tube with excellent roundness is obtained.