The oxidative reaction route from adsorbed species derived from adsorption of methanol on SnO2 has been investigated with Fourier transform infrared spectroscopy (FTIR). Molecularly adsorbed methanol, two types of adsorbed methoxide species, and the OH species were observed after methanol exposure at 310 K. Methanol was oxidized to the methoxide and the OH species via a deprotonation reaction at 310 K, and these species reacted to the dioxymethylene species at 373 K, The other reaction path to form the dioxymethylene species can be considered by methanol dehydrogenation via formaldehyde.