Provided is a fluorine-containing magnesium oxide light-emitting body having an ultraviolet light emission strength that is at least at the level of that of magnesium oxide containing more than 100 ppm of fluorine, despite containing less than 100 ppm of fluorine. The magnesium oxide light-emitting body has a light-emission peak in the ultraviolet region of 200-300 nm on the basis of excitation by an electron beam or ultraviolet rays, has an amount of contained fluorine with respect to magnesium of less than 100 ppm, and has a light-emission peak strength ratio with respect to the reflection peak (wavelength around 980 nm) of the excitation-light lamp of at least 20. The light-emitting body can be obtained by adding to a magnesium oxide precursor a fluorine compound at an amount resulting in 0.06-1.25 mol% of fluorine with respect to magnesium, firing, temporarily cooling, and then reheating.