Disclosed is an Mg-based structural material in which the surface of the base is coated with a film comprising apatite crystals as the main component thereof. The coating film and the base may be integrated with a magnesium hydroxide layer, and the surface of the coating film may be painted with a resin paint. The thickness of the coating film may be from 1 to 5 µm. The Mg-based structural material takes a low environmental load in the production process thereof.