Photocatalytic oxidation of methanol in air over titanium(IV) oxide with large surface area of 300 m2g-1 was examined using a flow-type reactor at room temperature and elevated temperatures (298 to 623 K). In the reactor, titanium(IV) oxide coated on the outer surface of a glass tube was photoirradiated by an external black light lamp and was heated by a heater inserted in the glass tube. At room temperature, methyl formate was formed as the main product with a high level of selectivity (91 mole%) without catalyst deactivation for 5 h. The activity increased with an increase in the reaction temperature and the high selectivity was maintained at temperatures up to 523 K, whereas combustion of methanol to carbon monoxide and dioxide occurred above 573 K. On the basis of FTIR data for adsorbed species on titanium(IV) oxide, a mechanism involving formation of methoxide on the surface of titanium(IV) oxide, photocatalytic oxidation of methoxide to formaldehyde and photocatalytic formation of methyl formate via dimerization of formaldehyde is proposed.