To provide a method and an apparatus for manufacturing a stepped deformed cross sectional copper bar material by which the flatness of a thin sheet part 9 can be secured by eliminating the occurrence of waving in the thin sheet part 9.

In the method for manufacturing the stepped deformed cross sectional copper bar material, a portion passing through a groove part 3 in a flat V-shaped die 1 in a flat sheet copper bar material 6 is formed as a thick sheet part 10 and a portion passing through a V-shaped projection 2 in the flat V-shaped die 1 is formed in the thin sheet part 9, thereby forming the stepped deformed cross sectional copper bar material. Wherein, the surface-treatment for reducing the difference between the surface roughness in the parallel direction and the surface roughness in the orthogonal direction is applied to the surface of at least V-shaped projection 2 in the flat V-shaped die 1 with respect to the moving direction of the flat sheet copper bar material 6, so that the stepped deformed cross sectional copper bar material is formed by using this flat V-shaped die 1.