Abstract: A self-sacrifice type metal corrosion inhibitor is prepared by dispersing one or more kinds of metal powder having a greater ionization tendency than that of a metal to be treated and a water-insoluble thermoplastic resin powder in water containing a water-soluble anticorrosion agent, a surface-active agent and a thickener to from a treatment solution. The treatment solution is applied to the surface of the metal to be treated, which is heated to melt the thermoplastic resin powder and form a thermoplastic resin layer fixed to the surface of the metal. It forms a metal corrosion-inhibiting layer fixed to the surface through the thermoplastic resin, which acts as an adhesive layer.