A manufacturing method of a sintered ceramic body mixes barium silicate with aluminum oxide, a glass material, and an additive oxide to prepare a material mixture, molds the material mixture and fires the molded object. The barium silicate is monoclinic and has an average particle diameter in a range of 0.3 μm to 1 μm and a specific surface area in a range of 5 m2/g to 20 m2/g. The aluminum oxide has an average particle diameter in a range of 0.4 μm to 10 μm, a specific surface area in a range of 0.8 m2/g to 8 m2/g. A volume ratio of the aluminum oxide to the barium silicate is in a range of 10% by volume to 25% by volume.