  We report the observations of the magneto-hydrodynamic waves propagating
along magnetic flux tubes in the solar photosphere. We identified 20 isolated
strong peaks (8 peaks for pores and 12 peaks for inter-granular magnetic
structure) in the power spectra of the l.o.s. (line-of-sight) magnetic flux,
the l.o.s. velocity, and the intensity for 14 different magnetic
concentrations. The observation is performed with the spectro-polarimeter of
the Solar Optical Telescope aboard the \emph{Hinode} satellite. The observed
phase relation between the magnetic and the photometric intensity fluctuation
would not be consistent with that caused by the opacity effect, if the magnetic
field strength decreases with height along the oblique line of sight. We
suggest that the observed fluctuations are due to longitudinal (sausage mode)
and/or transverse (kink mode) MHD waves. The observed phase relation between
the fluctuations in the magnetic flux and the velocity is consistent with the
superposition of the ascending wave and the descending wave reflected at
chromosphere/corona boundary (standing wave). Even with such reflected waves,
the residual upward Poynting flux is estimated to be $2.7 \times 10^{6}$ erg
cm$^{-2}$ s$^{-1}$ for a case of the kink wave. Seismology of the magnetic flux
tubes is possible to obtain various physical parameters from the observed
period and amplitude of the oscillations.
