The present invention provides a glass having a refractive index and a coefficient of thermal expansion close to those of quartz glass, respectively, and also having anti-devitrification properties excellent enough to avoid the development of defects such as devitrification on the glass surface even when it is molded by drawing process or reheat forming, more specifically an optical glass for use in optical communication devices, particularly an optical glass for use in a stub.The optical glass of the invention is composed of a borosilicate glass having a refractive index of from 1.44 to 1.46, a coefficient of thermal expansion of from 10×10−7 to 50×10−7/° C., and a liquidus viscosity of 105.5 dPa·s or more.