Disclosed is a surface treating agent for metallic materials that has various properties such as corrosion resistance and overcoating properties and, when used in coating-type surface treatment, particularly can form a film , which has excellent adhesion to the surface of metallic materials, and can fix, within the film, a component capable of functioning as a corrosion inhibitor for metallic materials. The surface treating agent for metallic materials comprises a silicic acid compound (A), an organoalkoxysilane (B), a metallic compound (C) containing at least one metal element selected from the group consisting of Zr, Ti, Co, Fe, V, Ce, Mo, Mn, Mg, Al, Ni, Ca, W, Nb, Cr, and Zn, at least one compound (D) selected from the group consisting of phosphoric acid compounds and fluoro compounds, water (E), and an alcohol (F) produced upon hydrolysis of the organoalkoxysilan (B). The molar concentration (mol/L) of the alcohol (F) in the treating agent has been regulated in a predetermined range.