In order to determine the structures of the electronic energy band of beta-alumina-type superionic crystals, photoemission spectra have been measured systematically using a beam line with synchrotron radiation. The information of the valence bands was obtained from photoemission spectra as all beta-alumina-type superionic crystals are constructed from the 2p orbitals of oxygen. The structures of the electronic energy bands of beta-alumina-type superionic crystals near Gamma point were determined from the results obtained in this work and from previous results concerning reflection spectra. The energy bands from the inner shells of the components of these materials were also determined.