A phosphor panel favorably employable for medical diagnosis of chest has a phosphor layer formed on a substrate by a gas phase-accumulation method, in which the phosphor layer is composed of a large number of phosphor columns standing parallel to each other, in which the phosphor columns have a mean diameter of 0.1 to 50 .mu.m at a top surface thereof, and there are no phosphor columns having a diameter larger than 200 .mu.m at the top surface.