An optical glass having high-refractivity and low-dispersion properties and containing, by mol %, 0.1 to 40% of SiO2, 10 to 50% of B2O3, wherein the mass ratio of the content of SiO2 to the content of B2O3, SiO2/B2O3, is 1 or less, 0.5 to 22% of ZnO, 5 to 50% of La2O3, and optionally other ingredients. The optical glass has a refractive index nd of 1.86 to 1.95 and an Abbe's number νd of (2.36−nd)/0.014 or more but less than 38, and a glass transition temperature of equal to or greater than 640° C.