The TiN films with the thickness of 0.1, 0.2, 0.5, 1.0, and 4.0 µm were coated on a steel substrate by the ion beam mixing method. The film had a strong fiber texture with <001> axis perpendicular to the film surface. The in-plane stress measurement was applicable to the thickness down to 0.1 µm of TiN films. The stress was a compression of around 2 GPa. The compressive stress was found to increase below the surface layer of 20 to 30 nm. Thinner films had a steeper increase of the compressive stress in the very-near surface region. The strain distribution measured by the SV method was nearly constant over the region of the penetration depth between 0.3 and 0.6 µm from the surface. The two-tilt method combined with the surface removal method showed a nearly constant distribution of compression in the subsurface region and a sharp increase near the interface to the substrate.