  Archival Suzaku data of the face-on spiral galaxy M101 were analyzed. An
intense emission line at 6.72^{+0.10}_{-0.12} keV was detected in the central
region. This line is identified with a K-line from He-like iron, which
indicates the existence of a thin thermal plasma with a temperature of several
keV. The iron line luminosity within the central 5 arcmin radius region is
estimated to be (2-12)x10^{37} erg s^{-1}. The origin of the iron emission line
is discussed.
