  Using ASCA, spatially integrated X-ray spectra of the central regions of M31
were studied. Data were accumulated over three different circular regions, with
the radii of 3', 6' and 12', all centered on the nucleus. The spectra are
relatively similar among the three regions. In the energy range above 1.5 keV,
the spectra are reproduced by a combination of a disk black-body component and
a black-body component, implying that the emission mainly comes from an
assembly of low-mass X-ray binaries. In energies below 1.5 keV, the spectra
involves two additional softer components, expressed with thin-thermal plasma
emission models of temperatures ~ 0.9 keV and ~ 0.3 keV. Over the central 12'
(2.4 kpc) region and in the 0.5-10 keV energy band, the binary component has a
luminosity of 2.6 x 10^{39} erg/s, while the two softer components both exhibit
luminosities of ~ 2 x 10^{38} erg/s. These results are compared with those from
other missions, including Chandra and XMM-Newton in particular. Discussion is
made on the nature of the two softer spectral components besides the binary
one.
