The present invention provides a ceramic material comprising magnesium, gallium, lithium, and oxygen as main components, wherein a crystal phase of a solid solution attained by dissolving gallium oxide and lithium oxide in magnesium oxide is a main phase. An XRD peak of a (200) plane of the solid solution with CuKα rays preferably appears at 2θ=42.91° or more which is larger than an angle at which a peak of a Cubic crystal of magnesium oxide appears, more preferably appears at 2θ=42.91° to 43.28°, and further preferably appears at 2θ=42.91° to 43.02°. In the ceramic material, a molar ratio Li/Ga of Li to Ga is preferably 0.80 or more and 1.20 or less.