OPTICAL GLASS, PREFORM AND OPTICAL ELEMENT

To provide an optical glass that can contribute to the weight saving of an optical element and an optical device having a refractive index (nd) and an Abbe number (νd) in desired ranges.SOLUTION: An optical glass comprises, in mass%, SiO2 component of more than 0% to 15.0% or less, B2O3 component of more than 0% to 17.0% or less, La2O3 component of 32.0-62.0%, and TiO2 component of 6.0-37.0%, has 2.00 or more of a refractive index (nd) and 20 or more and 30 or less of an Abbe number (νd), and the relation between the refractive index (nd) and the Abbe number (νd), and a specific gravity ρ satisfies 5.00≤(nd×2+νd)/ρ≤7.00.SELECTED DRAWING: Figure 1 【課題】屈折率（ｎｄ）及びアッベ数（νｄ）が所望の範囲内にありながら、光学素子や光学機器の軽量化に寄与することが可能な光学ガラスを提供する。【解決手段】光学ガラスは、質量％で、ＳｉＯ２成分を０％超１５．０％以下、Ｂ２Ｏ３成分を０％超１７．０％以下、Ｌａ２Ｏ３成分を３２．０～６２．０％、ＴｉＯ２成分を６．０～３７．０％含有し、２．００以上の屈折率（ｎｄ）を有し、２０以上３０以下のアッベ数（νｄ）を有し、屈折率（ｎｄ）とアッベ数（νｄ）、比重ρの関係が、５．００≦（ｎｄ×２＋νｄ）／ρ≦７．００の関係を満たす。【選択図】図１