  Solar active regions contain electric currents. Information on the
distribution of currents is important for understanding the processes of energy
release on the surface of the Sun and in the overlying layers. The paper
presents an analysis of the probability density function (PDF) of the absolute
value of the photospheric vertical electric current density ($|j_z|$) in 48
active regions before and after flares in 2010--2017. Calculation of $|j_z|$ is
performed by applying the differential form of Ampere's circuital law to
photospheric vector magnetograms obtained from observations of the Helioseismic
and Magnetic Imager (HMI) instrument onboard the Solar Dynamics Observatory
(SDO). It has been established that for the studied active regions PDF($|j_z|$)
is described by the Gauss function in the low-$|j_z|$ region ($|j_z| < 10110
\pm 1321$ statampere/cm$^2$) and the decaying power-law function in the region
of higher $|j_z|$ values. Also, for some active regions PDF($|j_z|$) can be
described by the special kappa-function. The distributions of the parameters of
the approximating functions are obtained using the least squares method. The
average absolute value of the power-law function index is $3.69 \pm 0.51$, and
$3.99 \pm 0.51$ of the kappa-function. No systematic changes in parameters
during the flares are detected. An explicit connection between the parameters
and the flare X-ray class, as well as with the Hale magnetic class of the
active regions, is not found. Arguments are presented in favor of the
suggestion that the Gaussian distribution in the low-value region of
PDF($|j_z|$) represents noise in the data, while the power-law "tail" reflects
the nature of electric currents in the solar active regions.
