A glass for chemical strengthening contains, in mole percentage on an oxide basis, 58 to 80% of SiO2, 13 to 18% of Al2O3, 0 to 5% of B2O3, 0.5 to 4% of P2O5, 4 to 10% of Li2O, 5 to 14% of Na2O, 0 to 2% of K2O, 0 to 11% of MgO, 0 to 5% of CaO, 0 to 20% of SrO, 0 to 15% of BaO, 0 to 10% of ZnO, 0 to 1% of TiO2, and 0 to 2% of ZrO2. A value of X is 30000 or more. The value of X is calculated based on the formula, X=SiO2×329+Al2O3×786+B2O3×627+P2O5×(−941)+Li2O×927+Na2O×47.5+K2O×(−371)+MgO×1230+CaO×1154+SrO×733+ZrO2×51.8, by using the contents in mole percentage on an oxide basis of components.