  We report results from X-ray and optical observations of the Galactic black
hole candidate MAXI J1828-249, performed with Suzaku and the Kanata telescope
around the X-ray flux peak in the 2013 outburst. The time-averaged X-ray
spectrum covering 0.6--168 keV was approximately characterized by a strong
multi-color disk blackbody component with an inner disk temperature of ~0.6
keV, and a power-law tail with a photon index of ~2.0. We detected an
additional structure at 5-10 keV, which can be modelled neither with X-ray
reflection on the disk, nor relativistic broadening of the disk emission.
Instead, it was successfully reproduced with a Comptonization of disk photons
by thermal electrons with a relatively low temperature (<~10 keV). We infer
that the source was in the intermediate state, considering its long-term trend
in the hardness intensity diagram, the strength of the spectral power-law tail,
and its variability properties. The low-temperature Comptonization component
could be produced in a boundary region between the truncated standard disk and
the hot inner flow, or a Comptonizing region that somehow developed above the
disk surface. The multi-wavelength spectral energy distribution suggests that
the optical and UV fluxes were dominated by irradiated outer disk emission.
