PURPOSE: To obtain the titled composition for coating, having low baking temperature and excellent hot-water resistance, etc., available at a low cost, and suitable for the baking on a substrate deforming at a high temperature, by using P2O5 as a main component, and compounding ZnO, Na2O, TiO2, etc. at specific molar ratios.

CONSTITUTION: Raw materials are weighed in a manner to obtain a glass composition composed of 20W55mol% P2O5, 15W55mol% RO (RO contains ≥8mol% ZnO as essential component and contains CaO, BaO, MgO and SrO as arbitrary component), 4W35mol% R2O (R2O is one or more oxides selected from Li2O, Na2O, K2O and Cs2O) and 0W20mol% TiO2. The raw materials are crushed, mixed, molten to a glassy state, quenched, and finely pulverized to obtain the objective glass composition having low melting point. The thermal expansion coefficient of the coating glass film prepared from the glass composition can be made close to that of the substrate such as a thin steel plate, and accordingly, a glass coating film having high adhesivity to the substrate can be produced.