To coat a thin metallic sheet with corrosion resistance and antifouling property on a metallic substrate surface by fusion jointing.

A thin metallic sheet 2 is jointed on the surface of a metallic substrate 1 by resistant welding, or the thin metallic sheet 2 and a fixing metal 7 are just overlaid on the surface on the metallic substrate 1, and then fusion jointing is carried out by arc welding so as to closely coat the thin metallic sheet on the surface of the metallic substrate. Thus, jointing strength is adequately secured and the welding heat input is restricted, resulting in the small thickness of the thin metallic sheet and the reduction of material cost.