A glass substrate includes, as a glass matrix composition as represented by mole percentage based on oxides, SiO2: 55%-75%, Al2O3: 2%-15%, MgO: 0%-10%, CaO: 0%-10%, SrO: 0%-10%, BaO: 0%-15%, ZrO2: 0%-5%, Na2O: 0%-20%, K2O: 5%-30%, and Li2O: 0%-5.0%. The glass substrate has a total content of alkali metal oxides, as represented by mole percentage based on oxides, of 10%-30%, a value obtained by dividing the total content of alkali metal oxides by the content of SiO2 of 0.50 or smaller, a value obtained by dividing the content of Na2O by a value obtained by subtracting the content of Al2O3 from a total content of Na2O and K2O of 0.90 or smaller, and an average coefficient of thermal expansion α1 at 50° C.-350° C. of 11 ppm/° C.-16 ppm/° C.