  We present and interpret several new X-ray features of the X-ray pulsar PSR
J1838-0655. The X-ray data are obtained from the archival data of CHANDRA,
RXTE}, and SUZAKU. We combine all these X-ray data and fit the spectra with
different models. We find that the joint spectra are difficult to fit with a
single power law; a broken power-law model with a break at around 6.5 keV can
improve the fit significantly. The photon index changes from $\Gamma$ = 1.0
(below 6.5 keV) to $\Gamma$ = 1.5 (above 6.5 keV); this indicates a softer
spectral behaviour at hard X-rays. The X-ray flux at 2-20 keV is found to be
1.6x10^{-11} ergs cm^{-2} s^{-1}. The conversion efficiency from the spin-down
luminosity is ~ 0.9% at 0.8-10 keV, which is much higher than that (~ 10^{-3}%
- 10^{-4}%) of the pulsars that show similar timing properties. We discuss
non-thermal radiation mechanisms for the observed high X-ray conversion
efficiency and find that emission from the magnetosphere of a greatly inclined
rotator is the most favorable interpretation for the conversion rate and the
pulse profiles at X-ray bands. A line feature close to 6.65 keV is also
detected in the spectra of SUZAKU/XIS; it might be the K$_\alpha$ emission of
highly ionised Fe surrounding the pulsar.
