  The results from the first three years observation in Telescope Array are
reviewed. The energy spectrum, mass composition, and anisotropy in arrival
directions of ultra-high energy cosmic rays are discussed. The energy spectrum
of cosmic rays with energies above $10^{18}$ eV is determined using the data of
the fluorescence detectors, surface detectors, and with a hybrid shower
reconstruction technique using the both data. The ankle structure is clearly
found at $10^{18.7}$ eV. The second bending point is also identified, at which
the flux of cosmic rays begins to decrease and the spectral index changes from
$E^{-2.68}$ to $E^{-4.2}$. The study of shower development using the
fluorescence detector data shows that proton is dominant in cosmic rays above
$10^{18.2}$ eV. No apparent anisotropies in the arrival direction of cosmic
rays are found. I also present further experimental extensions which are being
developed at the Telescope Array site.
