  The process of the vacuum polarization energy losses of high energy cosmic
rays propagating in the extragalactic space is considered. The process is due
to the polarization of Cosmic Background Radiation by a moving charged
particle. With the goal of the description of the process, the photon mass,
refractive indices and permittivity function for low and high energy photons
are found. Calculations show the rather noticeable level of the energy losses
for propagating protons with the enegies more than 10^6 - 10^7 GeV. The
influence of the polarization energy losses on propagation of cosmic rays is
discussed.
