The spectral hole-burning in SrFCl:Sm~(2+) at 77 K is studied. It has been obtained that the total area of holes in the inhomogeneous line shape is limited by the number of Sm~(3+) in the material and the maximum of total area (S_(hole)) of holes is proportional to the number of Sm~(3+). The integrated area (S_i) in the inhomogeneous line shape is proportional to the number of Sm~(2+) in the material. The value of'S_(hole)/S_i is equal to the ratio of the trivalent to the divalent samarium contents in the material.