The molecular properties of polystyrene modified by Frechet-type dendrons of the first-fourth generation containing polar CONH groups, were studied by means of the dielectric spectroscopy method in dilute solutions. The dispersion of the dielectric permittivity of dendronized polystyrene was found in benzene, chloroform and THF solutions in the electric field frequency range 0.2 kHz-10 MHz. It was established that the increase of dendron generation number leads to the growth of the relaxation times of dielectric polarization. It was found that the dipole moment of the monomer unit of the polystyrene molecules modified by first generation dendrons coincides with the dipole moment of CONH group.