A phosphor thin film is provided that has a high luminance, a satisfactory color purity sufficient to eliminate a need for filters, and a long luminance life. The phosphor thin film can be adapted to suit each element of red, green and blue in full color EL panels. The phosphor thin film includes a matrix material and a luminescent center. The matrix material is a sulfide containing at least an alkaline earth element, Ga and/or In, sulfur (S) and optionally, Al, or an oxysulfide further containing oxygen (O) in addition to the foregoing elements. Provided that A stands for the alkaline earth element and B stands for Ga, In and Al in the matrix material, the atomic ratio B/A is in the range: B/A=2.1 to 3.5.