Abstract: A high-refractive index, low-dispersion optical glass which is small in a change of imaging properties due to a change in temperature of the use environment, specifically one capable of realizing an absolute value of multiplication (?×?) of an average coefficient of linear expansion (?) at from ?30 to +70° C. and a photoelastic constant (?) at a wavelength of 546.1 nm of not more than 130×10?12° C.?1×nm×cm?1×Pa?1, is manufactured without using large qualities of components which are high in an environmental load and scarce mineral resources. The optical glass of the invention has an absolute value of multiplication (?×?) of an average coefficient of linear expansion (?) at from ?30 to +70° C. and a photoelastic constant (?) at a wavelength of 546.1 nm of not more than 130×10?12° C.?1×nm×cm?1×Pa?1; and contains more than 0% of SiO2, B2O3 and La2O3, more than 13% and less than 20% of (ZrO2+Nb2O5) and less than 2.0% of ZnO in terms of % by mass on the oxide basis.