An object is to provide a technique capable of forming a film having a dark black appearance and high corrosion resistance on a zinc plated component in a simple process, and a black coating film-forming vehicle component and/or fastening component that is obtained by: treating a surface of a zinc plated metal substrate with a black chemical conversion treatment agent containing trivalent chromium as an active ingredient, to form a black chemical conversion treatment film having an L value (brightness) of from 33 to 30; coating a black coating composition containing a black pigment in an amount of from 25 to 65% by weight in a thermosetting film-forming component and an alkoxysilane oligomer, on the black chemical conversion treatment film; and heat-curing the black coating composition thus coated.