A porous structural oxide film was formed on titanium-niobium alloys (TiNb) by anodic oxidation after cathodic pretreatment. The effects of titanium hydride compounds on the formation of an oxide film and the structural properties of a TiNb matrix were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and nanoindentation. The XRD spectra showed that composite films containing TiH 1.924 were formed by cathodic pretreatment and directly dissolved after anodic oxidation. Consequently, a thick and porous oxide surface was formed on a TiNb matrix, thereby increasing the bioactivity of TiNb. Nano-indentation showed that the elastic modulus of TiNb was reduced until it was close to that of bone tissue. These results showed that TiNb subjected to anodic oxidation after cathodic pretreatment had the potential to promote sufficient load sharing between the bone and the TiNb implant.