  Wide-band Suzaku data on the merging cluster Abell 3667 were examined for
hard X-ray emission in excess to the known thermal component. Suzaku detected
X-ray signals in the wide energy band from 0.5 to 40 keV. The hard X-ray (> 10
keV) flux observed by the HXD around the cluster center cannot be explained by
a simple extension of the thermal emission with average temperature of ~7 keV.
The emission is most likely an emission from a very hot (kT > 13.2 keV) thermal
component around the cluster center, produced via a strong heating process in
the merger. In the north-west radio relic, no signature of non-thermal emission
was observed. Using the HXD, the overall upper-limit flux within a 34'x34'
field-of-view around the relic is derived to be 5.3e-12 erg s-1 cm-2 in the
10-40 keV band, after subtracting the ICM contribution estimated using the XIS
or the XMM-Newton spectra. Directly on the relic region, the upper limit is
further tightened by the XIS data to be less than 7.3e-13 erg s-1 cm-2, when
converted into the 10--40 keV band. The latter value suggest that the average
magnetic field within the relic is higher than 1.6 uG. The non-thermal pressure
due to magnetic fields and relativistic electrons may be as large as ~20% of
the thermal pressure in the region.
