Vacuum-ultraviolet reflectance and photoemission spectra of VO 2, V 2 O 3, V 6 O 13, and V 2 O 5 are measured in order to investigate the 3d-band structures and electron-correlation effects. In the case of VO 2, drastic changes in the 3d (π* and d?)-band structures are found in both spectra through the metal-insulator phase transition. The π* and d? bands are found at the Fermi level and E B= 1.3 eV in the photoemission spectra of metallic VO 2. In the insulating phase, the π* valence band in the photoemission spectra becomes empty and a rise of the π* conduction band by about 0.5 eV is found in the reflectance spectra. This band shift through the phase transition may be a driving force of the metal-insulator transition of VO 2. The optical band gap between the d? valence and π* conduction bands is obtained as 0.7 eV in the insulating phase, to which the π*-d? correlation energy contributes partially.