PURPOSE: To secure the antirust property and to hold good workability, by pouring the molten metal of the ferrit stainless steel of suitable composition into the mold provided with the slab of the plain steel, and by limiting the thickness of the stainless steel coated layer formed on this steel slab.

CONSTITUTION: For example, a low carbon steel slab of 0.05% C with thckness (t) is previously installed in the mold; the molten steel at 1480°C, being constituted equivalently to AISI430 containing under 0.1% C and 11W20% Cr, is poured into this mold within the Ar atmoshere; the molten steel solidifies producing a composite steel ingot. This composite ingot is hot rolled according to the conventioanl process; hereby, directly or after being once annealed before cold rolling and annealing, the ferrit stainless steel coated layer is formed with the thickness above 30μ and under 1/3 of the total sheet gauge. Thus manufactured composite steel sheet has excellently improved ridging property without damaging the antirust property and the ductility as comparaed with the conventional ferrit stainless steel sheet, and also, the reduction of cost and the saving of resources can be accomplished.