We have developed an ultrahigh-resolution spin-resolved photoemission spectrometer equipped with a highly efficient mini Mott detector and an intense xenon plasma discharge lamp. Three-dimensional spin-polarization is determined by using a 90^o electron deflector situated between the hemispherical electron-energy analyzer and the Mott detector. The spectrometer achieves the energy resolution of 0.9 and 8 meV for non-spin-resolved and spin-resolved modes, respectively. By using the newly developed spectrometer, we have performed spin-and angle-resolved photoemission spectroscopy of bismuth thin film on Si(111) to investigate the spin structure of surface states. Unlike the normal Rashba splitting, the magnitude of the in-plane spin polarization is asymmetric across the zone center between the two elongated surface hole pockets. More surprisingly, we observed a giant out-of-plane spin polarization as large as the in-plane counterpart which switches the sign across the Γ⁻-M⁻ line. We discuss the present finding in terms of the breaking of time reversal symmetry and the many-body effects.