The electronic band structure of the ZnO(1010) surface has been studied by angle-resolved photoemission spectroscopy utilizing synchrotron radiation. Photon-energy-dependent measurements and K- and O-2-adsorption studies revealed that the O 2p dangling-bond state exists at 3.7 eV below the Fermi level at the Gamma point. Polarization-dependent measurements show that the state has dominant contribution of the O 2p(x) orbital (x is parallel to the (1210) direction) at the Gamma point. It is found that the O 2p dangling-bond band lies within the projected bulk bands along the GammaX and GammaX' axes in the surface Brillouin zone. This result settles a controversial issue on the energetic position of the O 2p dangling-bond band, which has been in dispute among theoretical studies. The dispersion widths are found to be 0.8 and 0.5 eV along the GammaX and GammaX' directions, respectively. (C) 2004 Elsevier B.V. All rights reserved.