Provided is a glass composition for protecting a semiconductor junction which contains at least SiO2, B2O3, Al2O3, ZnO and at least two oxides of alkaline earth metals selected from a group consisting of CaO, MgO and BaO, and substantially contains none of Pb, As, Sb, Li, Na and K, wherein an average linear expansion coefficient within a temperature range of 50° C. to 550° C. falls within a range of 3.33×10−6 to 4.13×10−6. A semiconductor device having high breakdown strength can be manufactured using such a glass material containing no lead in the same manner as a conventional case where “a glass material containing lead silicate as a main component” is used.