To impart excellent antifungal properties to a steel sheet without deteriorating its hot workability by providing the surface of a stainless steel sheet with a Cu layer of a specified thickness, heating it to a specified temp. range in a nonoxidizing atmosphere and diffusing Cu into the surface of the steel sheet.

As the stainless steel, generally used ones of martensitic series, ferritic series, austenite-ferrite two phase series or the like may be adopted, but the austenitic series one is not preferable. For providing the surface with a Cu layer, the method in which a Cu sheet and a stainless steel sheet are superposed, and rolling is executed at a room temp. is relatively easy, inexpensive and suitable for mass production. The thickness of the Cu layer is controlled to 5 to 25 μm. The stainless steel sheet provided with the Cu layer is heated in a nonoxidizing atmosphere. The nonoxidizing atmosphere is of an inert gas such as gaseous hydrogen, argon or nitrogen or a vacuum atmosphere. The heating temp. is regulated to the range of more than the m.p. of the Cu layer to <1300°C. In this case, as for the holding time, about ≤10 min is enough.