The radiation image conversion panel includes a substrate and a phosphor layer of columnar crystals formed on the substrate by vapor-phase deposition, with a column diameter distribution of the columnar crystals having two or more peaks. The process for producing a radiation image conversion panel prepares a substrate on which two or more types of projections different in diameter are formed and satisfies Expression "0.4R.ltoreq.r.ltoreq.0.8R" where R is a diameter of a largest projection and r is a diameter of any one of the remainder in the two or more types of projections, thereby making a surface of the substrate uneven and forms a phosphor layer on the uneven surface of the substrate by vapor-phase deposition.