A plated steel product having excellent resistance to corrosion, characterized in that it comprises, on a steel product, a Zn alloy plating layer having the composition that Mg: 1 to 10 wt. %, Al: 2 to 19 wt. %, Si: 0.01 to 2 wt. %, balance: Zn and inevitable impurities, with the proviso that the amounts of Mg and Al satisfy the relationship: Mg (%) + Al (%) ≤ 20 %, and having a plating layer structure of, for example, an intermetallic compound containing Mg; and a method for producing the plated steel product. Preferably, the plated product further comprises a Ni plating layer as a ground coat. Also provided is a precoated steel sheet having excellent resistance to corrosion, characterized in that it comprises, on the above plating layer, a chromate coating layer as an intermediate layer, and an organic coating layer as a top coat layer in a thickness of 1 to 100 νm, or it comprises, on the plating layer, a chromate coating layer in a thickness corresponding to 10 to 300 mg in terms of metallic chromium/m2, as a top coat layer. The above Zn alloy plating layer can further comprise one or more of 0.01 to 1 wt. % of In, 0.01 to 1 wt. % of Bi, and 1 to 10 wt. % of Sn.