  In this paper we use the model of extragalactic background light to
investigate the factors that have influence on the confusion noise. It was
shown that (1) Large-Scale Structure of the Universe is an important factor;
(2) gravitational lensing does not have a significant effect on the confusion
noise; (3) lower redshift limit of objects that contribute to the confusion
noise does not depend on the wavelength and is about $z_{min}\sim 0.5-0.6$,
while upper redshift limit gradually changes from $\sim4$ to $\sim3$ with the
increase of wavelength from 70$\mu m$ up to 2000$\mu m$; (4) at rather short
wavelengths ($\simeq70\mu m$) galaxies with luminosities in the range
$10^7L_\odot$ -- $10^9L_\odot$ give the most contribution to the confusion
noise, while at larger wavelengths (650-2000$\mu m$) their luminosities are
greater than $L\geq10^{10}L_\odot$; (5) contribution from objects with
different color characteristics is considered; (6) the variability of the
extragalactic background on the timescale from 1 day to 1 year is noticeable at
short wavelengths (70--350$\mu m$) and manifests at fluxes ${}^<_\sim$ 1~mJy.
