A glass ceramics sintered body includes a glass phase and a ceramics phase dispersed in the glass phase. The ceramics phase includes alumina grains and zirconia grains. The glass phase includes an MO—Al2O3—SiO2—B2O3 based glass, where M is an alkaline earth metal. An area ratio of the alumina grains is 13 to 30%, and an area ratio of the zirconia grains is 0.05 to 6%, on a cross section of the sintered body.