The effect of simultaneous irradiation of an oxygen-ion beam (O-IB) or an argon-ion beam (Ar-IB) on an oxygen-radical beam assisted evaporation (O-RBAE) was studied to deposit titanium-oxide films with high refractive indices at low substrate temperature. In O-RBAE, the oxygen-radical beam (O-RB) was irradiated to completely oxidize titanium Ti, which was simultaneously evaporated onto a glass substrate from an electron beam source. In addition to O-RB, O-IB or Ar-IB was simultaneously irradiated to make the deposited films dense onto the substrate. The substrate temperature rose to less than 100 degreesC during the film deposition. The refractive indices n, the film densities, and the morphology of the films deposited by O-RBAE combined with O-IB (O-RBAE/O-IB) and Ar-IB (O-RBAE/Ar-IB) were compared with those of the films deposited only by O-RBAE. In O-RBAE/O-IB, compared with O-RBAE, the n value increased from 2.37 to 2.51, the film density increased from 3.87 to 4.02 g cm(-3), and the morphology changed from a columnar-ne structure to homogeneous one. O-IB irradiation, therefore, made the deposited films denser. In O-RBAE/Ar-IB, on the other hand, the n value decreased from 2.37 to 2.32, and the film density decreased from 3.87 to 3.52 g cm(-3). As compared with O-IB irradiation, Ar-IB rather made the deposited films more porous. This proved that O-RBAE/O-IB was effective for depositing the titanium-oxide films with high refractive indices at low substrate temperature.