The paper describes a method of de-excitation times measurement of scintillators by a cathode-ray oscillograph. By approximation of the filter network of the oscillograph amplifier with one or more integrating constants, the corresponding equations have been obtained. Showing them graphically, there is a possibility for a fast determination of the de-excitation time of the examined substances. Moreover, there is a possibility for the measurement of ampitude yield of the slow de-excitation component with regard to the fast one by a direct analysis of the recorded oscillogram.