To produce the subject phosphor having suppressed unevenness of characteristics, and excellent in photostimulable light emitting amount, erasing characteristics and UV-fogged characteristics by charging a vessel with a mixture of raw materials for the phosphor so as to have a specific space-filling rate and a prescribed thickness in a baking step.

This method for producing a photostimulable phosphor comprises (A) a mixing step for preparing a raw material mixture for the phosphor by mixing the raw materials for the phosphor, (B) a baking step for charging a vessel with the obtained mixture so that the volume of the mixture may be 10-60% based on the storing volume of the vessel, and the difference of the maximum and the minimum of the charged thickness may be ≤50% of the average value, and baking the charged materials, and (C) a cooling step for cooling the baked product. The objective phosphor has a composition formula (Ba1-a, MIIa)FX.bmI.cMIII.dA:xLn [MII is an alkaline earth metal such as Sr; MI is a compound of an alkali metal such as Li; MIII is a compound of a trivalent metal such as Al; X is Cl, Br, I, or the like; Ln is a rare earth element such as Ge and Pr; A is a metal oxide such as Al2O3; 0≤(a)≤0.3; 0≤b; c≤2; 0≤d≤0.5; 0<x≤0.2].