  We present results of a study of the Galactic ridge X-ray emission (GRXE) in
hard X-rays performed with the IBIS telescope aboard INTEGRAL. The imaging
capabilities of this coding aperture telescope make it possible to account for
the flux from bright Galactic point sources whereas the wide field of view
permits to collect large flux from the underlying GRXE. Extensive study of the
IBIS/ISGRI detector background allowed us to construct a model that predicts
the detector count rate with $\sim1-2$% accuracy in the energy band 17-60 keV.
The derived longitude and latitude profiles of the ridge emission are in good
agreement with the Galactic distribution of stars obtained from infrared
observations. This, along with the measured hard X-ray spectrum of the Galactic
ridge emission strongly indicates its stellar origin. The derived unit stellar
mass emissivity of the ridge in the energy band 17-60 keV, $(0.9 - 1.2)\times
10^{27}$\lummass (assuming a bulge mass of $1-1.3 \times 10^{10} M_\odot$)
agrees with that of local (in the Solar neigborhood) accreting magnetic white
dwarf binaries - dominant contributors to the GRXE at these energies. In
addition, the shape of the obtained GRXE spectrum can be used to determine the
average mass of white dwarfs in such systems in the Galaxy as $\sim0.5
M_{\sun}$. The total hard X-ray luminosity of the GRXE is $L_{\rm 17-60 keV}
=(3.7\pm0.2)\times10^{37}$\lum in the 17--60 keV band. At energies 70--200 keV
no additional contribution to the total emission of the Galaxy apart from the
detected point sources is seen.
