[en] The equilibrium current fluctuations (thermal noise) for low-dimensional degenerate electron gas (1D, 2D) bounded in a narrow (short) channel, or in a thin film (3D) have been calculated within the semiclassical Boltzmann-equation approach. The analytical formulas for the autocorrelation functions have been derived for the complete degenerate case. The noise spectrum under ballistic regime of electron transport was found to be non-Lorentzian with decreased zero-frequency plateau and geometrical resonances at high frequencies depending on the size of the channel. The formulas for the conductivity (conductance) derived from the obtained analytical expressions for C₁(t) are exactly identical to the known formulas (e.g., to Fuchs size-effect formula for 3D case). Measurements of the size-dependent noise spectrum would give an additional information about the edge scattering of electrons. (author). 17 refs, 6 figs