[en] The results of measurements of the energy spectra and pitch-angle distributions of electrons with energies of 0.3-2.0 MeV in the inner belt, which were made on the Interkosmos-19 satellite in 1979, have been used to calculate the distribution function for constant values of the first and second adiabatic invariants. The shape of the distribution function indicates radial diffusion from an external source. The diffusion coefficient in the inner belt at L = 1.2-1.4 is determined from the radial diffusion equation