The present invention is a sintering material including a granule, the sintering material having an apparent tap density of 1.0 to 2.5 g/cm3, a 50% cumulative volume particle diameter (D50N) of 10 to 100 μm as measured before ultrasonication by laser diffraction/scattering particle size distribution analysis, a 50% cumulative volume particle diameter (D50D) of 0.1 to 1.5 μm as measured after ultrasonication at 300 W for 15 minutes by laser diffraction/scattering particle size distribution analysis, and an X-ray diffraction pattern in which the maximum peak observed in the 2θ angle range of from 20° to 40° is assigned to a rare earth oxyfluoride of the form LnOF when analyzed by X-ray diffractometry using Cu—Kα or Cu—Kα1 rays.