The three coupled oscillator model and its application to the explanation of optical-rotatory dispersion and circular dichroism of benzil crystal is discussed. The previously measured experimental data are approximated by the theoretical set of formulas provided by this model. The twelve-term formula, which was computed using our computer program, is derived from the interpretation of the optical-rotatory dispersion of benzil. Similarly, the circular-dichroism data are analyzed. Both the previously published experimental data and the latest measurements are used for this reason. The obtained results are compared and discussed with respect to the origin of the optical activity occurring in benzil crystal.