Abstract: A divalent metal fluorohalide phosphor having a compositional formula:(Ba.sub.1-x, M.sup.II.sub.x)F.sub.2.aBaX.sub.2 :yEu,zB(wherein, M.sup.II is at least one member selected from the group consisting of beryllium, magnesium, calcium, strontium, zinc, and cadmium, X is at least one member selected from the group consisting of chlorine, bromine, and iodine, and a, x, y, and z are numbers satisfying the respective conditions 0.5.ltoreq.a.ltoreq. 1.25, 0.ltoreq.x.ltoreq.1, 10.sup.-6 .ltoreq.y.ltoreq.2.times.10.sup.-1, and 0<z.ltoreq.2.times.10.sup.-1), when exposed to and allowed to absorb radiation or ionizing radiation and subsequently excited with a light of 450 to 800 nm of wave length, provides stimulated emission of light with heretofore unattainable high luminance.A radiation image storage panel is produced by depositing on a support a phosphor layer formed of the phosphor of this invention.