Regular measurements of fluxes of charged particles in the Earth’s atmosphere conducted by the Lebedev Physical Institute (LPI) made it possible to register since 1963 more than 500 cases of precipitation of energetic electrons in the northern polar latitudes. The obtained experimental data represent the world’s only database on the precipitation of electrons registered directly in the Earth’s atmosphere. Primary precipitating electrons are absorbed in the upper layers of the atmosphere. However, the fluxes of secondary photons generated by them can penetrate deep into the atmosphere, sometimes to heights of ~20 km, which are accessible for balloon measurements by the Lebedev Physical Institute. This paper presents a new technique for reconstructing the energy spectrum of precipitating electrons developed on the basis of the Monte Carlo simulation of the processes of electron propagation in the atmosphere. The applicability of the technique to the accumulated experimental data is shown, and new results are presented for individual events recorded in the atmosphere.