Titanium boron nitride (Ti,B)N films have been prepared by depositing Ti and B atom vapor on a (100) Si single crystal and an amorphous glass substrates under simultaneous irradiation of N ions, that is ion mixing and vapor deposition (IVD) technique. The transport ratio of metals and ion, (Bva+Tiva)/Nion, was fixed at 4, and the film thickness was supposed to be 1 m. With an increase in the evaporation ratio of B and Ti, Bva/Tiva, from 0 to 3, microstructure of the film was changed from fine triangular to granular morphology. It was confirmed by the XPS analysis that N ions were preferentially coordinated with Ti atoms when the Bva/Tiva was relatively low otherwise nitriding of B probably occurred. This result was also supported by the XRD spectra of the films. Knoop hardness of the (Ti,B)N films was strongly dependent on the Bva/Tiva. The highest hardness of approximately 5000 was observed at the Bva/Tiva=0.3; this implies that a small amount of alloying B considerably increases the film hardness.