This paper reports on an experimentally checked narrow-band-pass X-ray filter-monochromator which is able to separate a narrow X-band near the absorption edge of the required element. The experimental conditions have no effect on the energy position of maximum transmission of the filter. The transmission band of the filter corresponds approximately to the width of the core level of the selected element. In addition, the possibility of creating an X-ray narrow-band-pass filter-polarimeter is discussed. The range of applicability of such a device, in particular for research into inelastic X-ray scattering and in the anomalous diffraction scattering technique, is under consideration.