  Gluon distributions in real and virtual photons are calculated using
evolution equations in the NLO approximation. The quark distributions in the
photon determined on the basis of the QCD sum rule approach in ref.[1] are
taken as an input. It is shown that gluon distribution in the photon can be
reliably determined up to $x = 0.03 \div 0.05$ much lower than the
corresponding values in the case of quark distributions.Two variants of the
calculations are considered: (1) it is assumed that there are no intrinsic
gluons in the photon at some low normalization point $Q^2 = Q^2_0 \sim 1
GeV^2$; (2) it is assumed that gluonic content of the photon at low $Q^2_0$ is
described by gluonic content of vector mesons $\rho, \omega, \varphi$. The
gluon distributions in these two variants appear to be different. This fact
permits one to clarify the origin of nonperturbative gluonic content of the
photon by comparing the results with experiment. Structure functions $F_2(x)$
for real and virual photon are calculated and it is shown that in the region $x
\geq 0.2$ where QCD approach is valid, there is a good agreement with
experiment.
