To investigate the effects of post-coat substrate quenching on the tribological properties of TiN film, a specimen was prepared in which the steel substrate (carbon tool steel, JIS SK3) was quenched after TiN coating, and the ball-on-disk type wear test was carried out using a ZrO 2 ball. The delamination initiation life of TiN film was improved by the high adhesive strength of TiN film obtained by post-coat substrate quenching. The specific wear rate was also improved by post-coat substrate quenching, although TiN hardness was lower than that of the conventional type specimen, which was coated with TiN after substrate quenching. The improvement in the specific wear rate could be explained as follows. In the post-coat substrate quenching process, TiN was partly oxidized and titanium oxide, which acted as a lubricant, was formed on the TiN surface. The formation of titanium oxide resulted in a reduction in the friction coefficient and consequently a lower specific wear rate was obtained.