An objective is to provide a radiation image conversion panel exhibiting excellent graininess and reduced x-ray damage (luminance degradation). A radiation image conversion panel comprising a support and provided thereon, a stimulable phosphor layer containing a stimulable phosphor in a polymer resin, wherein a luminescence intensity ratio of (A) stimulable phosphor particles comprising a smallest average particle diameter to (B) stimulable phosphor particles comprising a largest average particle diameter is 0.8-1.2, provided that a total average particle diameter of all the stimulable phosphor particles is 3.0-10.0 .mu.m, an average particle diameter of (A) is 2.0-6.0 .mu.m, an average particle diameter of (B) is 6-15 .mu.m, and a content of (A) or (B) is within the range of at least 10% by weight and at most 90% by weight, based on the total stimulable phosphor content.