A radiation image storage panel has a phosphor layer composed of energy-storing phosphor particles and a polymer binder and satisfies the following conditions; T.sub.1.times.d.gtoreq.660; T.sub.2.times.d.gtoreq.660; D.gtoreq.3.4 [T.sub.1 is a transmittance (%) of the phosphor layer at a peak wavelength of a stimulation spectrum of the phosphor particles; T.sub.2 is a transmittance (%) of the phosphor layer at a peak wavelength of a stimulated emission spectrum of the phosphor particles; d corresponds to a value of 10,000.times.W/.rho. [W is a weight of the phosphor particles in a unit area of the phosphor layer expressed by mg/cm.sup.2 and .rho. is a density of the energy-storing phosphor expressed by g/cm.sup.3]; and D is a density of the energy-storing phosphor particles contained in the phosphor layer expressed by g/cm.sup.3].