  The wide-band energy spectrum of NGC6240 over the range 0.5-200keV is
investigated using the RXTE and ASCA data. The RXTE data provide the spectrum
beyond the ASCA range (0.5-10 keV) with significant detection of signals up to
20keV and the upper limits above 20keV. The spectrum above 10keV is found to be
very flat. A strong iron-K emission line discovered in the previous ASCA
observation is also confirmed with the RXTE PCA. These results provide further
evidence for the dominance of a reflection component, i.e. emission from cool
material illuminated by an AGN. By fitting the spectra obtained with RXTE and
ASCA simultaneously, we satisfactorily modeled the AGN spectrum with a Compton
reflection component and probably a transmitted AGN component penetrating
through a thick absorber. The X-ray luminosity of the AGN is estimated to be in
the range 4x10^43 - 6x10^44 ergs/s in the range 2-10keV, which categorizes
NGC6240 among the most luminous Seyfert nuclei. The ratio of the 2-10keV X-ray
luminosity to the infrared luminosity, L_X(2-10keV)/L_IR, is 0.01 - 0.1, which
implies a quite substantial, if not dominant, contribution of AGN to the
infrared luminosity.
