[en] The primordial objects with the masses of galaxies or their clusters formed at early stages such as z > 10 can play a powerful role of gravitational lenses and their random multiple scattering brings an effective screening for the cosmic background radiation. In a cold-dark-matter dominant model with the white-noise spectrum of initial density perturbations, it is shown that, if the primordial objects with the masses 10¹²h^-1 (solar mass) are in the nonlinear stage at the epochs 1 + z = 10 ∼ 20, the objects with 6 x 10¹⁴h^-1 (solar mass) are in the nonlinear stage at 1 + z = 6.3 ∼ 14, and accordingly the small-scale anisotropy of the radiation may be smoothed-out within 13 ∼ 28 minutes by this gravitational screening, where the Hubble constant H_o = 100 h km s^-1 Mpc^-1. (author)