Intended is a phosphor of the formula: (A1-xBx)3C5O12 wherein A is Y, Gd, and/or Lu, B is Ce and/or Tb, C is Al and/or Ga, and 0.002≦x≦0.2. A phosphor precursor is prepared by suspending gamma-alumina particles having a specific surface area of at least 50 m2/g and dissolving a rare earth element salt in water to form a suspended aqueous to solution, adding urea thereto, heating the solution to form mixed fine particles of gamma-alumina and rare earth element salt, separating, and firing the mixed fine particles at 600-1,000° C. to form mixed oxide fine particles of rare earth oxide and alumina.