Method of manufacturing a decorative article, a decorative article, and a timepiece

A method of manufacturing a decorative article, including a first coating formation step of forming a first coating of primarily TiN on a substrate; a second coating formation step of forming a second coating on the first coating by means of a dry plating method using a target containing 70.0 wt %≦85.0 wt % Au and 15.0 wt %≦30.0 wt % Cu; a heat treatment step of promoting formation of a solid solution of the constituents of the second coating by applying a heating process that heats the substrate on which the first coating and the second coating are disposed to 300° C.≦395° C. and then applying a cooling process; and an acid treatment step that, of the constituents of the second coating to which the heating process was applied, removes the constituents not forming a solid solution by applying an acid treatment.