A radiation image storage panel comprising a support and phosphor layers provided thereon which comprise a binder and a stimulable phosphor dispersed therein, characterized in that said phospher layers comprise the first phosphor layer on the support side and the second phosphor layer provided on the first phosphor layer, and that the mean particle size of the stimulable phosphor contained in said first phosphor layer is smaller than the mean particle size of the stimulable phosphor contained in said second phosphor layer.