A glass for chemical strengthening has a Young's modulus E of 70 GPa or more. The glass satisfies X1+X2+X3 being 1760 or less. Here, X1 is a numerical value equivalent to a value [unit: kPa/° C.] obtained by multiplying the Young's modulus E by an average coefficient α of thermal expansion at 50° C. to 350° C., X2 is a numeral value equivalent to a value of a temperature Tf [unit: ° C.] at which a viscosity of the glass reaches 100 MPa·s, and X3 is a numerical value equivalent to a value of a difference [unit: 105 Pa·s] between the viscosity (100 MPa·s) at the Tf and a viscosity η+10 at a temperature 10° C. higher than the Tf.