  The Centaurus cluster (z=0.0104) was observed with the X-ray Imaging
Spectrometer (XIS) onboard the Suzaku X-ray satellite in three pointings, one
centered on the cluster core and the other two offset by +-8' in declination.
To search for possible bulk motions of the intracluster medium, the central
energy of He-like Fe-K line (at a rest-frame energy of 6.7 keV) was examined to
look for a positional dependence. Over spatial scales of 50 kpc to 140 kpc
around the cluster core, the central line energy was found to be constant
within the calibration error of 15 eV. The 90% upper limit on the line-of-sight
velocity difference is |Delta_v|< 1400 km/s, giving a tighter constraint than
previous measurements. The significant velocity gradients inferred from a
previous Chandra study were not detected between two pairs of rectangular
regions near the cluster core. These results suggest that the bulk velocity
does not largely exceed the thermal velocity of the gas in the central region
of the Centaurus cluster. The mean redshift of the intracluster medium was
determined to be 0.0097, in agreement with the optical redshift of the cluster
within the calibration uncertainty. Implications of the present results for the
estimation of the cluster mass are briefly discussed.
