A technical object of the present invention is to devise an alkali-free glass that has a high etching rate in a HF-based chemical and a high strain point while having excellent productivity (particularly, devitrification resistance), to thereby reduce the production cost of a glass substrate, and then increase thinning efficiency and reduce the thermal shrinkage of the glass substrate in a production process of a display panel. In order to achieve the above-mentioned object, a glass substrate of the present invention includes as a glass composition, in terms of mol %, 65% to 75% of SiO2, 11% to 15% of Al2O3, 0% to 5% of B2O3, 0% to 5% of MgO, 0% to 10% of CaO, 0% to 5% of SrO, 0% to 6% of BaO, and 0.01% to 5% of P2O5, and has a molar ratio (MgO+CaO+SrO+BaO)/Al2O3 of from 0.7 to 1.5.