TiN films were deposited onto high speed steel (SKH9) by plasma assisted chemical vapor deposition (PACVD) using a TiCl4/N2/H2/Ar gas mixture at around 50$0^{circ}C$. The effects of the deposition temperature, R.F. power and TiCl4 concentration on the deposition of TiN and the microhardness of TiN film were investigated. The crystallinity and the microhardness of TiN films were improved with increase of the deposition temperature. Optimum deposition temperature in this study was 50$0^{circ}C$, because a softening or phase transformation of the substrate occurred over 50$0^{circ}C$. A large increase of the film growth rate with a strong(200) preferred orientation was obtained by increasing R.F. power. Much chlorine content of about 10at.% was found in the deposited films and resulted in relatively low average microhardness of about 1, 500Kgf/$ extrm{mm}^2$ compared with the theoretical value(~2, 000Kgf/$ extrm{mm}^2$).