Free surface roughening is the phenomenon in which the surface roughness on the free surface of polycrystalline metals increases with plastic deformation. The free surface roughening adversely affects the forming limit, aesthetics, and surface characteristics. Thus, it is important to clarify its mechanism. The series of conventional studies on the free surface roughening show empirically that the surface roughness increases linearly with the equivalent strain. However, the influence of deformation mode on the rate of the surface roughening has not been clarified. The authors continuously observe the evolution of the surface roughening in C1220 under various deformation modes such as uniaxial tension, plane strain tension, and equal biaxial tension using a laser microscope. The deformation modes affect the surface roughening especially as the equivalent strain increases. It is thought that this result is caused by the change in the surface area with the plastic deformation. By removing the effect, new deformation mode independent material constant of free surface roughening can be determined successfully.