The present invention relates to a light-transmitting ceramic sintered body which contains air voids having pore diameters of 1 μm or more but less than 5 μm at a density within the range of from 10 voids/mm3 to 4,000 voids/mm3 (inclusive), while having a closed porosity of from 0.01% by volume to 1.05% by volume (inclusive). With respect to this light-transmitting ceramic sintered body, a test piece having a thickness of 1.90 mm has an average transmittance of 70% or more in the visible spectrum wavelength range of 500-900 nm, and the test piece having a thickness of 1.90 mm has a sharpness of 60% or more at a comb width of 0.5 mm.