The density of vacant states (DVS) of Pt(100)-(1 X 1) single crystal surface is investigated by means of disappearance potential spectroscopy (DAPS). Probing hydrogen adsorption is used in order to suppress the strong diffraction background and to display the desirable features in difference spectra. Local density of states is calculated for the several top layers of semi-infinite Pt(100)-(1 X 1) plane. The spectra features are in a good agreement with the peculiarities of electronic structure that resulted from calculations. The comparison of experimental and theoretical data shows that hydrogen atoms adsorbed on the Pt(100)-(I X 1) surface at 300 K primarily interact with platinum atoms of the second layer.