The insertion of Ag+ into NbO2F narrowed the band gap from 3.2 eV (NbO2F) to 3.0 eV (Ag-NbO2F), which shifted the light absorption edge from the UV light region to the near-violet light region. The photocatalytic activities of NbO2F and Ag-NbO2F were evaluated by the decomposition of gaseous 2-propanol (IPA) under 400-530 and 300-400 nm light irradiations. Ag-NbO2F could decompose IPA to CO2 via acetone under both irradiation conditions. The value of the quantum efficiency was of the same order under both 400-530 and 300-400 nm light irradiations, which suggested the complete hybridization of the Ag4d and O2p orbitals in the valence band of Ag-NbO2F resulted in the 400-530 nm light sensitivity. The density of states calculations also supported the complete mixing of Ag4d and O2p.