We propose in this paper a new approach to solution of the inverse problem as applied to thermal sounding of the atmosphere. The approach is based on application of the Green's function to the regularized, by Tikhonov method, integro-differential equation. It is tested by solving a closed numerical model problem and then comparing the result with that obtained by classical Tikhonov method. It is noted that the approach provides a higher stability of the regularized solution. The data obtained with the HIRS/2 device (NOAA satellite) have been processed using this approach.