Titanium oxy-nitride (TiNO) films were deposited on surfaces of stainless steel SUS304 at temperatures of 400-770 ºC using an ion-beam assisted deposition technique constructed from an electron beam evaporator for Ti evaporation and a microwave ion source for ionizing nitrtogen gas. Most of the deposited TiON films consisted of (60 –80)% TiN and (40-20)%  TiO_2, and the fraction of TiO₂ increased with increasing substrate temperature. In comparison with an experiment performed by changing stainless steel to silicon wafer, the formation of TiON finds to due to oxygen degassed from stainless steel used as the substrates. Hardness of TiON films varied in the range from 160 Gpa to 260 Gpa with increasing substrate temperature. The lattice parameters of the TiON films depended weakly substrate temperature although it depended strongly on nitrogen ion energies. On the other hand, their Young’s modulus depended weakly nitrogen ion energies  although  it depended strongly on substrate temperature. However, when the TiON films were deposited at temperatures  higher than 700º C, the thickness of the TiON films became significantly thinner and the hardness became significantly smaller. The degradation in hardness on the TiON films deposited at high temperatures is caused by forming layers  containing nitride such as Cr₂N, CrFe, Fe₂N and Fe₄N, having small hardness, in a surface region of the stainless steel.