Provided is an optical glass having high refractivity and high dispersibility, having good moldability in precision pressing, and having high transmittance and good internal quality, of which the transmittance reduction with time is prevented. The optical glass has a Pt content of at most 1.5 ppm, and is characterized in that, when a sample of the glass polished on both surfaces and having a thickness of 10 mm is irradiated with UV and/or visible light at a light-receiving energy of at most 0.4 mW·cm−2 for at least 200 hours, then the difference in the internal transmittance to light having a wavelength of 420 nm, before and after the irradiation (before irradiation—after irradiation) of the sample, as calculated in terms of the sample having a thickness of 10 mm, is at most 0.1.